Links for Keyword: Hormones & Behavior

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By Lisa Feldman Barrett My husband found me sobbing on the kitchen floor. My job was in upheaval, my travel schedule was grueling, and with two hours left before my next departure, I’d discovered that my laptop was dead. This was the moment my husband walked in to console me, and in an impressive feat of bad timing, he also asked whether I was premenstrual. I went from sobbing to supernova in about two seconds, enraged by his presumption that surging female hormones were responsible for my emotional distress. The only thing that saved him was that, a few days later, I discovered that he’d been right. I am a scientist who studies the nature of emotions. For most of my scientific career, I didn’t believe that women systematically had emotional eruptions right before their period, even though I experienced them occasionally. Studies suggested that women who believe in premenstrual syndrome, when asked about it in retrospect, tend to misremember the symptoms as more severe than they were. The evidence for PMS overall was inconsistent. Certainly, I knew of no neurological reason that women should feel, just before their period, that the world was crashing down on them. My doubt was also political in nature. During my clinical internship over 20 years ago, my boss, a psychiatrist, asked me to research how PMS prevents women from thinking clearly. I told him he was a relic of the Stone Age. Women were as consistently clearheaded as men, if not more so. But recently, a researcher in my lab, Joe Andreano, an expert on female hormones, showed me some surprising data. As a woman’s levels of progesterone and estrogen vary, so does the connectivity between two brain networks: the default mode network and the salience network. These networks play key roles in creating your emotional life. If I hadn’t seen the data with my own eyes, I wouldn’t have believed it. © 2019 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 26317 - Posted: 06.10.2019

Wency Leung A new Canadian study on how the birth control pill affects a woman’s ability to think is the latest to address a decades-old knowledge gap researchers say needs to be fixed: How oral contraceptives impact the brain. The study aims to test the working memory of around 60 young women who use oral contraceptives, says researcher Laura Gravelsins, a PhD student with the Einstein Lab on cognitive neuroscience, gender and health at the University of Toronto. Gravelsins is among a number of researchers exploring an area that has historically been overlooked. Since the introduction of the pill in the 1960s, hormonal contraceptives – which contain estrogen, progestin, or a combination of both – have become a preferred option for many women. Yet, due, in part, to past assumptions that the brain operates separately from the rest of body and a general lack of research into women’s health, scientists are only now investigating how they may influence mood and cognition. Another area that needs exploration is how sex hormones, including those naturally produced by the body, influence developing brains. At the University of British Columbia, researchers are currently recruiting 300 girls, ages 13 to 15, to study what role sex hormones may play in their emotional development. “We need more research,” says Dr. Gillian Einstein, a professor of psychology at University of Toronto and the Wilfred and Joyce Posluns Chair in Women’s Brain Health and Aging. “Women should demand more research on this.”

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 26110 - Posted: 04.03.2019

By Jane E. Brody Dr. Gayatri Devi’s patient, a 55-year-old former headmistress, had good reason to be distraught. The woman had a yearlong history of progressive memory loss and behavioral problems and was referred to Dr. Devi, a neurologist, with a possible diagnosis of frontotemporal dementia. As Dr. Devi recounted in the journal Obstetrics & Gynecology, the woman’s once prodigious memory had seriously deteriorated and she’d become increasingly irritable. She had difficulty organizing tasks, keeping track of belongings, setting goals, making plans and seeing them through. Yet the results of medical and neurological tests and brain scans were normal. Noting that the woman had gone through menopause a year earlier, Dr. Devi traced her symptoms to the decline in estrogen stimulation of the brain that occurs in all women at menopause with varying effects. Some are more sensitive to falling estrogen levels than others. With a likely diagnosis of menopause-related cognitive impairment, the doctor prescribed hormone-replacement therapy. Within 15 months, the woman’s behavioral symptoms had disappeared and her learning ability and memory were back to normal. She was able to complete a demanding graduate program and assume a new leadership position in education. This woman’s case was admittedly extreme, but Dr. Devi told me that “60 percent of women go through menopause-related cognitive impairment” that, when serious enough to be brought to medical attention, is too often misdiagnosed as “mild cognitive impairment,” a precursor to dementia. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 14: Attention and Consciousness
Link ID: 25793 - Posted: 12.17.2018

by Lena Simon Four limbs. Warm blood. A love for cheese. And a hatred for infidelity. Although this may sound characteristic of the average Wisconsinite, the previous is actually also true for the California mouse. A recent University of Wisconsin news release revealed research that shows California pair-bonded mice become increasingly vocal after infidelity experiences. Experiments were designed to test how communication changes after mice have been given the opportunity to be “unfaithful” to their bonded mate. The California deer mouse, or Peromyscus californicus, is part of only 3 to 5 percent of mammal species that practice any kind of monogamy, per research from the National Science Foundation. At UW, research on the California mouse is ongoing. Josh Pultorak, a biology instructor at Madison Area Technical College and UW’s Wisconsin Institute for Discovery, led this research. He and his collaborators identified several types of sounds that the California mouse makes, all of which are ultrasonic — unable to be heard by the human ear unless slowed down to about 5 percent of their original speed. These include chirps — or “sweeps,” which are usually more peaceful sounds — and barks, which indicate aggression. Microbes in your gut could hold cure to diabetesThere are millions of microbes living in your gut. They help you digest and access nutrients your own organs would Read… The Badger Herald, 1995 - 2018

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 25637 - Posted: 11.02.2018

Sukanya Charuchandra R. Liu et al., “Perception of social interaction compresses subjective duration in an oxytocin-dependent manner,” eLife, 7:e32100, 2018. External stimuli can affect our perception of time. Researchers in China set out to test whether a person’s social skills and perception of social interactions alters their sense of time. Subjects viewed two motion sequences depicting two humans composed of dots of light. The first video clip showed sociable behavior between the figures, such as passing an object, while the second showed no interaction—the figures moved independently of each other. The subjects had to indicate which clip appeared to last longer. Overall, volunteers found the clips with communicative behavior to be shorter, even when that wasn’t true. This “temporal compression effect” was not as pronounced in less sociable test subjects, as measured by their Autism Spectrum Quotient, a questionnaire-based assessment that determines where people fall on the neurotypical or autistic scale. “It not only highlights the idiosyncrasy of subjective time but also demonstrates that our perception of the world (something as basic as time) is ingrained with our personality traits,” writes coauthor Wen Zhou of the Chinese Academy of Sciences’ Institute of Psychology in an email to The Scientist. © 1986 - 2018 The Scientist

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
Link ID: 25306 - Posted: 08.08.2018

By Daniela Lamas Incompletely understood at best, after more than a century of false starts and research gains. So we learn in “Aroused,” an eye-opening new book that traces the history of endocrinology through a sequence of crisp, meticulously researched, and often surprisingly funny tales from the turn of the 20th century to today. Though hormones have entered common parlance — we have growth hormone and sex hormones and hormone replacement therapy — it was not always this way. Randi Hutter Epstein, an accomplished author who has a medical degree and a master’s of public health, illuminates more than a century of false starts and research gains as she explains the ways these chemical messengers control the daily work of our bodies. At the same time, she leaves us wondering how much of our current understanding of hormones is in fact “true” and how much may ultimately be disproved. This is a novel contribution. While most of the literature on hormones has been confined to medical text or limited to a single hormone (estrogen, for example), Epstein’s approach is wide-ranging. Consider this story. The year was 1924, and two teenagers in Chicago bludgeoned a younger boy to death. The new field of endocrinology was exploding at the time, and their lawyers proposed a provocative theory to avoid the death penalty: Hormones were at fault. After extensive X-rays, interviews, and measures of metabolism, doctors testified that the teenagers had severely impaired hormonal glands and had committed the grisly murder under the influence of hormones gone awry. They were sentenced to life in prison. Copyright 2018 Undark

Related chapters from BN8e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 25262 - Posted: 07.28.2018

by Melissa Healy An extra shot of testosterone, it seems, makes a man act like an animal. You know the type: one of those male birds that unfurls some of its most spectacular feathers when the ladies are around, or the buck who uses his crown of antlers to advertise his virility. In short, an animal prone to making showy displays of his power, beauty or wealth to win mates, gain allies and intimidate competitors. But for humans — American men, at least — new research suggests that this testosterone-driven display of prowess finds its expression in a preference for status goods. Whether it’s in his choice of top-shelf alcohol at the club, the watch on his wrist or the clothes he wears, a man under the influence of the male sex hormone is going to reach for the product that says to potential mates (and to competitors for those mates), “U can’t touch this.” This pursuit of status in the choice of manufactured goods is called “positional consumption.” It’s been a hot topic among evolutionary psychologists and now is finding its way into the study of marketing. Researchers from the Wharton School of the University of Pennsylvania gave a supply of gel to 243 men, ages 18 to 55, and asked them to rub it all over their upper body. Some of the gels contained testosterone, others a placebo. Then the researchers asked the subjects to look at pictures and descriptions of five pairs of items — including watches, jeans and jackets — and judge which ones they preferred. © 1996-2018 The Washington Post

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 25210 - Posted: 07.16.2018

NPR's Lulu Garcia-Navarro talks with Dr. Randi Hutter Epstein about her new book Aroused, which tells the story of the scientific quest to understand human hormones. LULU GARCIA-NAVARRO, HOST: What do sleep, sex, insulin, mood and hunger have in common? Well, they're all controlled by hormones. But just a century ago, the power of our chemical messengers was barely understood. A new book by Dr. Randi Hutter Epstein called "Aroused" tells the stories of the scientists who work to explore and explain our hormones. Dr. Epstein joins us now from our New York bureau. Welcome to the program. RANDI HUTTER EPSTEIN: Thanks for having me. GARCIA-NAVARRO: The book is organized around stories from key moments in hormone research. And I have to say, many of the studies they were doing in the early days were pretty gruesome. EPSTEIN: When we say study, we tend now to think of the randomised clinical controlled trial. You know, you have one sample here. You compare it to another. When they were doing studies, they were doing sort of weird experiments on people and dogs and all kind of things. So there was Harvey Cushing. He was one of the first people to talk about that pituitary tumors can really muck you up and like send a lot of hormones awry. But here's what he tried to do that didn't work out that's kind of a wacky experiment. He had a 48-year-old man that had a pituitary tumor that was making him have double vision and headaches and other endocrine issues. And Harvey Cushing thought, what if we take a nice, healthy pituitary of a baby that just died if there is a newborn that didn't make it and just implant that in this old man, and then we just revive him and he'd be back to normal. Newspapers got a hold of it, as media tends to do. And there were wonderful headlines like baby brain, you know, broken brain fixed by baby. And it went wild in terms of, wow, we can now cure broken, old brains. And, spoiler alert, let's just say that we don't replace baby pituitary glands into grownups when they have pituitary tumors anymore.

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 25168 - Posted: 07.03.2018

Erika Engelhaupt The first scientific experiment on hormones took an approach that sounds unscientific: lopping off roosters’ testicles. It was 1848, and Dr. Arnold Berthold castrated two of his backyard roosters. The cocks’ red combs faded and shrank, and the birds stopped chasing hens. Then things got really weird. The doctor castrated two more roosters and implanted a testicle from each into the other’s abdomen. As Randi Hutter Epstein writes in a new book, each rooster “had nothing between his drumsticks but a lone testicle in his gut — yet he turned back into a full-fledged hen-chaser, red comb and all.” It was the first glimpse that certain body parts must produce internal secretions, as hormones were first known, and that these substances — and not just nerves — were important to the body’s control systems. Today, we know that hormones are chemical messengers shaping everything from sex and development to sleep, stress, mood, metabolism and behavior. Yet few of us know much about these powerful substances coursing through our bodies. That ignorance makes Aroused — titled for the Greek meaning of the word hormone — an invaluable guide. Epstein, a medical writer and M.D., tells the history of hormone research from that first rooster experiment, but cleverly moves back and forth through time, avoiding any hint of dry recitation. She explores the scientists who discovered and deciphered the effects of important hormones, as well as the personal stories of how people’s lives have been profoundly changed by these chemicals. |© Society for Science & the Public 2000 - 2018

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 25141 - Posted: 06.26.2018

By Randi Hutter Epstein My son Jack was born in London a month before his due date. The pediatrician said he was fine and we could go home. A few minutes later another doctor came in and asked to draw blood to try to figure out why Jack was premature. I refused, because we had already been given the go-ahead to leave. I heard the doctor tell the nurses to mark in my medical record, “Mother refuses treatment for her son.” “I’m not refusing treatment! I’m refusing a needless test!” I said from my bed. To which she mumbled, “Write down, ‘Mother is hormonal.’” And so began my rant. I stormed out of my room, dressed only in my husband’s white T-shirt and nestling my 12-hour-old son to my chest, and hollered after the fleeing doctor, “I am not hormonal!” The truth is I was hormonal. I had just given birth, so my progesterone (the hormone that maintained my pregnancy) had plummeted and my oxytocin (the hormone that squeezed my uterus to get the baby out, got the milk flowing and fostered mother-baby bonding) had skyrocketed. But that’s not what the doctor meant when she used the word “hormonal.” She meant I was a woman going off the rails. In 1939, James E. King, the president of the American Association of Obstetricians, Gynecologists and Abdominal Surgeons, devoted part of his presidential address to hormones and women’s craziness, or as he called it, their “peculiarities” and “inconsistencies.” He said hormone therapy, which was brand new at the time, would not only treat conditions like menstrual irregularities and infertility but would also help women manage their emotions and make them prettier (estrogen would supposedly bring back aging women’s youthful splendor). Then he concluded with this snide remark: “Will she, as some timid souls fear, mentally and physically dominate and enslave us as we in the past enslaved her? Probably not; so long as she is controlled by her reproductive glands, she will remain basically the same lovable and gracious homemaker.” © 2018 The New York Times Company

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 25057 - Posted: 06.05.2018

By Kerry Grens Neena Schwartz, a reproductive biologist at Northwestern University who discovered the hormone inhibin and its role in the regulation of reproductive cycles, died this month (April 15). She was 91. “She was a tremendous scientist, a pioneer for women in the sciences, and a leader in our discipline of endocrinology,” Teresa Woodruff and Kelly Mayo, both of Northwestern University, write in a memorial in Endocrine News. Among numerous leadership roles throughout her career, Schwartz founded the American Women in Science (AWIS) in 1971 and was a president of the Endocrine Society in the early 1980s. Schwartz was born in Baltimore, earned her undergraduate degree from Goucher College, and received her doctorate from Northwestern University in 1953. After a faculty position at the University of Illinois College of Medicine, she joined Northwestern in 1973 and remained as a professor there until her retirement in 1999. Her early work focused on rats’ hormonal cycles, and the insight she derived from her studies contributed to a basic understanding of the so-called HPG axis, the hypothalamic-pituitary-gonadal crosstalk of hormones that controls reproduction. Schwartz later discovered a peptide-based feedback system controlling hormone levels in the ovaries, and described the hormone inhibin, which blocks follicle stimulating hormone (FSH). The presence of inhibin had been proposed decades earlier, but nobody had searched for it in the follicle fluid of ovaries—until Schwartz and her colleague at the University of Maryland, Cornelia Channing took up the cause. Channing had sent Schwartz the fluid, and Schwartz found that it made FSH levels drop. © 1986-2018 The Scientist

Related chapters from BN8e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 24925 - Posted: 05.01.2018

By RANDI HUTTER EPSTEIN Getting a high testosterone reading offers bragging rights for some men of a certain age — and may explain in part the lure of testosterone supplements. But once you are within a normal range, does your level of testosterone, the male hormone touted to build energy, libido and confidence, really tell you that much? Probably not, experts say. Normal testosterone levels in men range from about 300 to 1,000 nanograms per deciliter of blood. Going from one number within the normal zone to another one may not pack much of a punch. “You don’t see the big improvement once men are within the normal range,” said Dr. Shalender Bhasin, an endocrinologist and professor of medicine at Harvard Medical School. The largest differences in terms of energy and sex drive are when men go from below-normal to normal levels. A 2015 study in JAMA found that sex drive improved among men who went from about 230, considered low, to 500, around the middle of what’s considered normal. There was no difference among men who moved within the normal range from 300 to 500. Testosterone does influence muscle size. The more testosterone a man takes, the larger the muscle — regardless of starting level, one reason the hormone is popular with young bodybuilders. But testosterone supplements do not seem to help frail older men walk farther or get out of chairs more easily, goals that doctors typically look for in aiding older patients. Beginning at age 30, testosterone levels drop, on average, about 1 percent a year. About 5 percent of men between the ages of 50 and 59 have low levels of testosterone along with symptoms like loss of libido and sluggishness, according to a few small studies. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 24792 - Posted: 03.28.2018

By Nicola Davis Your book is all about reproductive hormones, and their impact on our behaviour. It only focuses on female hormones. Why not look at men’s too? Two reasons. One is that the focus of research in my lab is to look at women’s hormones. The other is that I think there are problems with how people have viewed hormones and women, and I really want to debunk those myths, then pursue some of the implications for further exploring links between women’s hormones and their behaviour. I think they are really important for women’s wellbeing. You say that some people, including women, have pushed back against discussing the influence of hormones. Why is that? I get a strong sense that if you ascribe a woman’s behaviour to biology, people will automatically think that women are automatons, driven by their hormones and unable to regulate their own behaviour. That is false. There is a female stereotype, whereby any time a woman does something a little bit difficult to understand, then it is hormones that make women “irrational”. But nobody says that about men. For that reason, those who are concerned about women achieving equality with men worry that if we talk about women and hormones, then people will say such things as women shouldn’t hold higher office and so on. That’s silly, because men have hormones, too. Are you surprised by how recently we have begun investigating the impact of hormones on women? One reason is that scientists were content for many decades with studying the male as the default sex, and that was in part because women had cycles that made them messy. If you are doing a scientific experiment, you don’t want noise, you don’t want variation, you want everything to be strictly controlled. © 2018 Guardian News and Media Limited

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 24746 - Posted: 03.13.2018

Aimee Cunningham Internist Gail Povar has many female patients making their way through menopause, some having a tougher time than others. Several women with similar stories stand out in her mind. Each came to Povar’s Silver Spring, Md., office within a year or two of stopping her period, complaining of frequent hot flashes and poor sleep at night. “They just felt exhausted all the time,” Povar says. “The joy had kind of gone out.” And all of them “were just absolutely certain that they were not going to take hormone replacement,” she says. But the women had no risk factors that would rule out treating their symptoms with hormones. So Povar suggested the women try hormone therapy for a few months. “If you feel really better and it makes a big difference in your life, then you and I can decide how long we continue it,” Povar told them. “And if it doesn’t make any difference to you, stop it.” At the follow-up appointments, all of these women reacted the same way, Povar recalls. “They walked in beaming, absolutely beaming, saying, ‘I can’t believe I didn’t do this a year ago. My life! I’ve got my life back.’ ” That doesn’t mean, Povar says, that she’s pushing hormone replacement on patients. “But it should be on the table,” she says. “It should be part of the discussion.” Hormone replacement therapy toppled off the table for many menopausal women and their doctors in 2002. That’s when a women’s health study, stopped early after a data review, published results linking a common hormone therapy to an increased risk of breast cancer, heart disease, stroke and blood clots. The trial, part of a multifaceted project called the Women’s Health Initiative, or WHI, was meant to examine hormone therapy’s effectiveness in lowering the risk of heart disease and other conditions in women ages 50 to 79. It wasn’t a study of hormone therapy for treating menopausal symptoms. |© Society for Science & the Public 2000 - 2018.

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 24512 - Posted: 01.10.2018

/ By Deborah Blum I’m hesitating over this one question I want to ask the scientist on the phone, a federal researcher studying the health effects of soy formula on infants. I worry that it’s going to sound slightly Dr. Frankenstein-esque. Finally, I spill it out anyway: “Are we talking about a kind of accidental experiment in altering child development?” The line goes briefly silent. “I’m a little worried about the word ‘experiment,’” replies Jack Taylor, a senior investigator at the National Institute of Environmental Health Sciences, a division of the National Institutes of Health. Taylor and his colleagues in North Carolina have been comparing developmental changes in babies fed soy formula, cow-milk formula, and breastmilk. His group’s most recent paper, “Soy Formula and Epigenetic Modifications,” reported that soy-fed infant girls show some distinct genetic changes in vaginal cells, possibly “associated with decreased expression of an estrogen-responsive gene.” But his first reaction is that my phrasing would, incorrectly, “make it sound like we were giving children a bad drug on purpose.” The research group, he emphasizes, is merely comparing the health of infants after their parents independently choose a preferred feeding method. No one is forcing soy formula on innocent infants. “No, no, that’s not what I meant,” I explain with some hurry. “I wasn’t suggesting that you were experimenting on children.” Rather, I was wondering whether we as a culture, with our fondness for all things soy, have created a kind of inadvertent national study. Soy accounts for about 12 percent of the U.S. formula market and I’ve become increasingly curious about what this means. Because the science does seem to suggest that we are rather casually testing the effect of plant hormones on human development, most effectively by feeding infants a constant diet of a food rich in such compounds. Copyright 2017 Undark

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23912 - Posted: 08.03.2017

By JANE E. BRODY Problems with estrogen and testosterone, the body’s main sex hormones, tend to attract widespread public interest. But we might all be better off paying more attention to a far more common endocrine disorder: abnormal levels of thyroid hormone. Thyroid disorders can affect a wide range of bodily functions and cause an array of confusing and often misdiagnosed symptoms. Because the thyroid, a small gland in the neck behind the larynx, regulates energy production and metabolism throughout the body, including the heart, brain, skin, bowels and body temperature, too much or too little of its hormones can have a major impact on health and well-being. Yet in a significant number of people with thyroid deficiencies, routine blood tests fail to detect insufficient thyroid hormone, leaving patients without an accurate explanation for their symptoms. These can include excessive fatigue, depression, hair loss, unexplained weight gain, constipation, sleep problems, mental fogginess and anxiety. Women of childbearing age may have difficulty getting pregnant or staying pregnant. Although thyroid disorders are more common in adults, children, whose cognitive and physical development depend on normal thyroid function, are not necessarily spared. In a review article published last year in JAMA Pediatrics, doctors from the Children’s Hospital of Philadelphia pressed primary care doctors to recognize childhood thyroid disease and begin treatment as early as the second week of life to ensure normal development. Hypothyroidism — low hormone levels — in particular is often misdiagnosed, its symptoms resembling those of other diseases or mistaken for “normal” effects of aging. Indeed, the risk of hypothyroidism rises with age. Twenty percent of people over 75, most of them women, lack sufficient levels of thyroid hormone that, among other problems, can cause symptoms of confusion commonly mistaken for dementia. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23866 - Posted: 07.24.2017

By THERESE HUSTON “Does being over 40 make you feel like half the man you used to be?” Ads like that have led to a surge in the number of men seeking to boost their testosterone. The Food and Drug Administration reports that prescriptions for testosterone supplements have risen to 2.3 million from 1.3 million in just four years. There is such a condition as “low-T,” or hypogonadism, which can cause fatigue and diminished sex drive, and it becomes more common as men age. But according to a study published in JAMA Internal Medicine, half of the men taking prescription testosterone don’t have a deficiency. Many are just tired and want a lift. But they may not be doing themselves any favors. It turns out that the supplement isn’t entirely harmless: Neuroscientists are uncovering evidence suggesting that when men take testosterone, they make more impulsive — and often faulty — decisions. Researchers have shown for years that men tend to be more confident about their intelligence and judgments than women, believing that solutions they’ve generated are better than they actually are. This hubris could be tied to testosterone levels, and new research by Gideon Nave, a cognitive neuroscientist at the University of Pennsylvania, along with Amos Nadler at Western University in Ontario, reveals that high testosterone can make it harder to see the flaws in one’s reasoning. How might heightened testosterone lead to overconfidence? One possible explanation lies in the orbitofrontal cortex, a region just behind the eyes that’s essential for self-evaluation, decision making and impulse control. The neuroscientists Pranjal Mehta at the University of Oregon and Jennifer Beer at the University of Texas, Austin, have found that people with higher levels of testosterone have less activity in their orbitofrontal cortex. Studies show that when that part of the brain is less active, people tend to be overconfident in their reasoning abilities. It’s as though the orbitofrontal cortex is your internal editor, speaking up when there’s a potential problem with your work. Boost your testosterone and your editor goes reassuringly (but misleadingly) silent. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 14: Attention and Consciousness
Link ID: 23776 - Posted: 06.26.2017

Cassie Martin Long typecast as the strong silent type, bones are speaking up. In addition to providing structural support, the skeleton is a versatile conversationalist. Bones make hormones that chat with other organs and tissues, including the brain, kidneys and pancreas, experiments in mice have shown. “The bone, which was considered a dead organ, has really become a gland almost,” says Beate Lanske, a bone and mineral researcher at Harvard School of Dental Medicine. “There’s so much going on between bone and brain and all the other organs, it has become one of the most prominent tissues being studied at the moment.” At least four bone hormones moonlight as couriers, recent studies show, and there could be more. Scientists have only just begun to decipher what this messaging means for health. But cataloging and investigating the hormones should offer a more nuanced understanding of how the body regulates sugar, energy and fat, among other things. Of the hormones on the list of bones’ messengers — osteocalcin, sclerostin, fibroblast growth factor 23 and lipocalin 2 — the last is the latest to attract attention. Lipocalin 2, which bones unleash to stem bacterial infections, also works in the brain to control appetite, physiologist Stavroula Kousteni of Columbia University Medical Center and colleagues reported in the March 16 Nature. After mice eat, their bone-forming cells absorb nutrients and release a hormone called lipocalin 2 (LCN2) into the blood. LCN2 travels to the brain, where it gloms on to appetite-regulating nerve cells, which tell the brain to stop eating, a recent study suggests. © Society for Science & the Public 2000 - 2017.

Related chapters from BN8e: Chapter 5: Hormones and the Brain; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 23762 - Posted: 06.22.2017

Paula Span “During the past four weeks, have you been tired? Been exhausted? Had difficulty getting motivated to do anything at all?” These questions — which a substantial chunk of the population probably could answer in the affirmative — appeared on a questionnaire used in a major European study published recently in The New England Journal of Medicine. The authors were researching the effectiveness of a drug that is widely, if controversially, used to treat older adults with subclinical hypothyroidism, better known as a slightly underactive thyroid. So many Americans take that medication — levothyroxine (brand name Synthroid) — that it topped the list of prescription drugs dispensed in the United States in 2015, according to the research firm QuintilesIMS Institute. With 121 million prescriptions annually, levothyroxine outpaced statins, blood pressure meds — and everything else. A Johns Hopkins survey published last year found that more than 15 percent of older Americans were taking it. So you’d think these study results would come as shocking news: The European team reported that in older people with mild hypothyroidism, the drug had no significant effect on symptoms. At all. Instead, the results bolstered what a number of geriatricians and endocrinologists have suspected for years. “It’s a strong signal that this is an overused medication,” said Dr. Juan Brito, an endocrinologist at the Mayo Clinic. “Some people really need this medicine, but not the vast majority of people who are taking it.” © 2017 The New York Times Company

Related chapters from BN8e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23522 - Posted: 04.22.2017

By RONI CARYN RABIN Television ads for “low T” have sparked a rise in the use of testosterone gels, patches and injections by older men in recent years, according to a new report. But anyone hoping that a dose of testosterone will provide an easy antidote for sagging muscles, flagging energy and a retiring sex drive may find the results of recent government studies of the sex hormone sobering. The latest clinical trials, published over the past year, are the first rigorous ones to assess the potential beneficial effects of testosterone treatment for older men with abnormally low levels of the hormone. Scientists followed 790 men age 65 and older who had blood testosterone levels below 275 nanograms per deciliter of blood, well below the average for healthy young men and lower than would be expected with normal aging. The men also had symptoms reflecting their low hormone levels, like loss of sex drive. Half the participants were treated with testosterone gel, and half were given a placebo gel. The studies reported mixed results, finding that over the yearlong study period, testosterone therapy corrected anemia, or low levels of red blood cells, which can cause fatigue, and increased bone density. But a study to see if testosterone improved memory or cognitive function found no effects. Meanwhile, a red flag warning of possible risks to the heart emerged from the studies: Imaging tests found a greater buildup of noncalcified plaque in the coronary arteries of men treated with testosterone for a year, an indicator of cardiac risk, compared with those who were given a placebo gel. The findings of plaque were not a complete surprise; many reports have tied testosterone use to an increase in heart attacks, and the Food and Drug Administration already requires testosterone products to carry warnings of an increased risk of heart attacks and stroke (men at high risk of cardiovascular disease were not allowed to participate in the latest trials). But observational studies, which are weaker, have yielded mixed results over all, with one study published last month finding that men taking testosterone actually had fewer heart problems. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23413 - Posted: 03.28.2017