Links for Keyword: Hormones & Behavior

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Don’t Sweat It: Premenopausal Women, Reproductive State, and the Joy of Night Sweats

By Kate Clancy I tend to go to bed freezing, especially so in the winter, so I pile our flannel sheet, blanket, and down comforter over me when I settle in to sleep. A few times each menstrual cycle, clustered together in the luteal phase between ovulation and menses, I wake up from sleep completely soaked in my own sweat – not a delightful sight or experience. Usually I get up, change pajamas, and try to find a dry spot on the bed to go back to sleep (I promise the sheets eventually get washed, but I’m not about to wake my husband – and sometimes daughter – to change the bed at 3am). These night sweats started when I was still intensively breastfeeding my daughter and was marathon training, when she was under a year old. At first, I thought it was because we were co-sleeping and we slept next to each other. But I never experienced them next to my husband before that point, and he is a six foot four heat generating machine. When the marathon was over and I returned to less strenuous activity, breastfeeding frequency was also starting to decline. I didn’t get any night sweats again for quite some time. Then there was roller derby. At first, roller derby was a pastime, a recreational activity where I got to learn something totally new and hang out with women I respected. But of course, being the competitive person I am, it became an obsession, and in addition to roller derby practices I was working out quite a lot on my own time. Over the last year I’ve made additional nutritional adjustments to further improve my performance, and I’ve increased the intensity of my off-skates workouts. I work out a minimum of five hours a week, but in the middle of the season it is usually a minimum of nine hours per week. © 2012 Scientific American

Related chapters from BN: 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: 17609 - Posted: 12.17.2012

The ‘Love Hormone’ as Sports Enhancer

By GRETCHEN REYNOLDS Is playing football like falling in love? That question, which would perhaps not occur to most of us watching hours of the bruising game this holiday season, is the focus of a provocative and growing body of new science examining the role of oxytocin in competitive sports. Oxytocin is, famously, the “love hormone,” a brain peptide known to promote positive intersocial relations. It makes people like one another, especially in intimate relationships. New mothers are awash in oxytocin (which is involved in the labor process), and it is believed that the hormone promotes bonding between mother and infant. New-formed romantic couples also have augmented bloodstream levels of the peptide, many studies show. The original attraction between the lovers seems to prompt the release of oxytocin, and, in turn, its actions in the brain intensify and solidify the allure. Until recently, though, scientists had not considered whether a substance that promotes cuddliness and warm, intimate bonding might also play a role in competitive sports. But the idea makes sense, says Gert-Jan Pepping, a researcher at the Center for Human Movement Sciences at the University of Groningen in The Netherlands, and the author of a new review of oxytocin and competition. “Being part of a team involves emotions, as for instance when a team scores, and these emotions are associated with brain chemicals.” Copyright 2012 The New York Times Company

Related chapters from BN: Chapter 5: Hormones and the Brain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 17517 - Posted: 11.21.2012

Hormone may help protect monogamous relationships

By Melissa Healy, Los Angeles Times If retired Army Gen. David H. Petraeus had gotten an occasional dose of supplemental oxytocin, a brain chemical known to promote trust and bonding, he might still be director of the Central Intelligence Agency, new research suggests. A study published Tuesday in the Journal of Neuroscience has uncovered a surprising new property of oxytocin, finding that when men in monogamous relationships got a sniff of the stuff, they subsequently put a little extra space between themselves and an attractive woman they'd just met. Oxytocin didn't have the same effect on single heterosexual men, who comfortably parked themselves between 21 and 24 inches from the comely female stranger. The men who declared themselves in "stable, monogamous" relationships and got a dose of the hormone chose to stand, on average, about 6 1/2 inches farther away. When researchers conducted the experiment with a placebo, they found no differences in the distance that attached and unattached men maintained from a woman they had just met. Even when an attractive woman was portrayed only in a photograph, the monogamous men who received oxytocin put a bit more distance between themselves and her likeness. But when the new acquaintance was a man, administration of oxytocin did not prompt attached men to stand farther away than single men, the researchers reported. Los Angeles Times, Copyright 2012

Related chapters from BN: 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: 17495 - Posted: 11.17.2012

Oxytocin changes partnered men's behaviour

by Andy Coghlan Men with partners increase the space they feel comfortable with between themselves and an attractive woman if exposed to the bonding hormone oxytocin. René Hurlemann at the University of Bonn in Germany and colleagues gave men either a sniff of oxytocin or a placebo before asking them to choose the ideal distance for an interaction with a woman. The distance that they felt was comfortable significantly increased after sniffing oxytocin, but only for men in relationships. The team conclude that oxytocin discourages partnered but not single men from getting close to a female stranger. Journal reference: Journal of Neuroscience, DOI: 10.1523/jneurosci.2755-12.2012 © Copyright Reed Business Information Ltd.

When the Cuddle Hormone Is a Home Wrecker

By Gary Stix First off, this study on a molecule tied to social interaction was conducted in animals. So I’m supposed to turn on the siren and the flashing red light here to let you know that the headline you just read might not apply in humans. Still, the animals in question, prairie voles, are a special case, models of faithfulness that put humans to shame when it comes to the delicate topic of monogamy. Once hitched, the rodents stick with their mates for life—an example of moral pulchritude in the animal kingdom that many of us human sinners can never hope to emulate. It could easily become the state animal for whole regions of the U.S. For just that alone, the implications of the experiment in question are particularly intriguing. The new research shows that oxytocin, the bonding hormone, is sometimes capable of turning the upstanding rodent into an anti-social lout, making the study results more compelling in many ways than if they were reported in errant humans. So the man-bites-dog headline stays. This all came up when Karen Bales, a professor at University of California, Davis, wanted to know what would happen if oxytocin gets administered for lengthy intervals, not the short-term dosing that has occurred in the multitude of previous vole studies that linked the hormone to monogamous behavior. In their experiment, Bales and team gave either a low, medium or high dose through the nose to 29 voles, and a saline solution to 14 controls At first, the animals became all cuddly as in previous studies But after three weeks, an entire vole childhood (from weaning to sexual maturity), they started breaking bad. Males did not engage in the normal behavior of “pair bonding,” that drives them to look for the girl of their dreams. And female voles’ natural mothering instinct seemed to disappear: when placed nearby young pups that were not their own, they didn’t dote, as they are wont to do. The cuddle hormone had turned the rodents into meanies. © 2012 Scientific American

Related chapters from BN: 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: 17379 - Posted: 10.17.2012

Men with high testosterone may be more honest

(Relaxnews)—In a study of more than 90 men, scientists from the University of Bonn, Germany, found that subjects treated with a dose of testosterone before the study told fewer lies than those who received a placebo. "Testosterone has always been said to promote aggressive and risky behavior and posturing," says researcher and neuroscientist Bernard Weber. However, more recent studies indicate that it also fosters social behavior. Prior research has suggested that the hormone may actually cause people to be more "prosocial" in that they voluntarily act in the interest of others, writes the Atlantic magazine, but exactly how the hormone influences behaviors isn't understood. For this latest study, 46 subjects were treated with testosterone by applying it to the skin in gel form, while 45 subjects received a placebo. The next day, the subjects played a dice game in which it was easy for the men to lie to earn more money, with no possibility of being caught. The study was designed so that it was impossible even for the researchers to detect whether a subject was lying or not. Rather, they used statistics to analyze reported earnings that were higher than probability would allow, inferring from these how honest the subjects were being. While many people in the study lied about the game, there was a noticeable difference between the men boosted with testosterone and those who weren't—the testosterone group avoided the temptation to cheat more often. Blood tests confirmed the results that high testosterone levels were linked with more honest game playing. "Test subjects with the higher testosterone levels had clearly lied less frequently than untreated test subjects," says co-author Armin Falk. "This result clearly contradicts the one-dimensional approach that testosterone results in anti-social behavior." The study was published last week in the journal PLoS One . http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0046774 © 2012 NY Times Co.

Korean Eunuchs Outlived Uncastrated Peers

by Gisela Telis In the industrialized world, women live at least 5 years longer, on average, than men. Scientists have attributed that difference to everything from healthier habits to hardier cells. Now, a new study that analyzes the longevity of eunuchs, or castrated men, suggests that testosterone may play a part in shortening men's lives. The idea that testosterone, the male sex hormone, affects lifespan isn't new. Neutered dogs and other animals that have had their sources of testosterone removed often live longer than their intact counterparts. But studies on the connection between castration and longevity in humans are harder to come by, and the results have been inconclusive. A 1969 study of institutionalized patients in Kansas found that castrated men lived an average of 14 years longer than other men in the same facility, but a 1993 study of Italian castrati (singers castrated as boys to preserve their high voices) found nothing unusual about their longevity. Almost 5 years ago, biologist Kyung-Jin Min of Inha University in Incheon, Korea, found himself considering this lack of data while watching a Korean TV drama about eunuchs. Min began to wonder if Korea's rich historical records could shed light on the link between castration and longevity in humans. Until the late 19th century, Korean rulers employed eunuchs to serve the royal court. These eunuchs were allowed to marry and adopt castrated boys as their sons. The Yang-Se-Gye-Bo, a genealogical record of the eunuch families, has survived, and it documents the birth and death dates and other personal details of 385 eunuchs who lived between the mid-16th century and the mid-19th century. © 2010 American Association for the Advancement of Science.

Drugs in Search of a Disease-Men’s Edition

By Judy Stone In one sense, it is refreshing to see men being the target of pharma, after all these years of women being the focus of relentless—and misleading—advertising. On the other, we’re seeing the start of yet another pharma campaign to dupe the public by the unnecessary medicalization of symptoms to create new drug markets. I used to be a fairly enthusiastic pharma fan, but over recent years have become increasingly disillusioned. The hype over testosterone is the latest example of why. With so many pressing problems in the world, I wish pharma would focus their attention on doing something more useful with their energies. I thought it started with drugs for “hot flashes,” but Karen Roush set me straight about hormone therapy, reporting that “It all started with men in ancient civilizations eating the penis and testicles of animals as a cure for impotence.” (And to think that Maryn McKenna just warned us of the dangers of kissing cats! This early hormone therapy sounds a bit dicier.) In the 1940s, estrogen was able to be extracted from horse urine in large quantities, enabling a supply for treating women “suffering from estrogen deficiency.” Dr. Robert Wilson, a prominent New York gynecologist, founded a private trust in 1963 to promote estrogen use. Pharmaceutical companies provided $1.3 million to this “trust;” they, of course, stood to profit handsomely from their investment in Wilson’s endeavor. Wilson is described as being “evangelical” in his crusade to save women from the “decay” of menopause. He was quite successful, with his 1966 book, Feminine Forever, selling 100,000 copies in the first seven months alone. His theme, “A Plea for the Maintenance of Adequate Estrogen from Puberty to Grave,” expounded in a mainstream medical journal, was adopted both by the medical profession and by the popular press. © 2012 Scientific American

How Testosterone May Alter the Brain After Exercise

By GRETCHEN REYNOLDS It’s widely accepted among scientists that regular exercise transforms the brain, improving the ability to remember and think. And a growing and very appealing body of science has established that exercise spurs the creation of new brain cells, a process known as neurogenesis. But just how jogging or other workouts affect the structure of the brain has remained enigmatic, with many steps in the process unexplained. A new study published last month in Proceedings of the National Academy of Sciences may fill in one piece of the puzzle, by showing that male sex hormones surge in the brain after exercise and could be helping to remodel the mind. The research was conducted on young, healthy and exclusively male rats – but scientists believe it applies to female rats, too, as well as other mammals, including humans. The decision to use only males was carefully considered. “We’ve known for a while that estrogen,” the female sex hormone, “is produced in the brain” not just of female animals but also, to some degree, in males, says Bruce S. McEwen, the director of the Laboratory of Neuroendocrinology at Rockefeller University in New York and an author of the study, which also involved scientists from the University of Tsukuba in Japan and other institutions. Estrogen has been well studied and has many effects, he said, including, scientists suspect, new brain cell growth. But far less has been known about the role of male sex hormones in mammalian brains, particularly after exercise. While both sexes produce male sex hormones, males produce far more of it – mostly in the gonads but, the researchers suspected, also in the brain. Copyright 2012 The New York Times Company

Testosterone marketing frenzy draws skepticism

By Matthew Perrone, Associated Press "Do you have a decrease in libido?" "Have you noticed a recent deterioration in your ability to play sports?" "It could be Low-T." Welcome to the latest big marketing push by the nation's drug companies. In this case, it's a web page for Abbott Laboratories' Androgel, a billion-dollar selling testosterone gel used by millions of American men struggling with the symptoms of growing older that are associated with low testosterone, such as poor sex drive, weight gain and fatigue. Androgel is one of a growing number of prescription gels, patches and injections aimed at boosting the male hormone that begins to decline after about age 40. Drugmakers and some doctors claim testosterone therapy can reverse some of the signs of aging — even though the safety and effectiveness of such treatments is unclear. "The problem is that we don't have any evidence that prescribing testosterone to older men with relatively low testosterone levels does any good," says Dr. Sergei Romashkan, who oversees clinical trials for the National Institute on Aging, a part of the National Institutes of Health conglomerate of research centers. Low testosterone is the latest example of a once-natural part of getting old that has become a target for medical treatment. Bladder problems, brittle bones and hot flashes have followed a similar path: from inconvenient facts of life, to ailments that can be treated with drugs. The rise of such therapies is being fueled by both demographics and industry marketing. © 2012 NBCNews.com

Researcher accused of misleading pregnant women

by Sara Reardon Freedom of information requests have revealed that pregnant women may not have been given all the facts before taking an experimental treatment to prevent female fetuses from being masculinised as a result of a rare genetic disorder. Research has provided some evidence that dexamethasone, a drug normally prescribed to relieve inflammation, can prevent girls with a rare hormonal disease from developing male genitalia and same-sex attraction if they are treated as fetuses. But as yet, no clinical studies show that this treatment is safe, says Alice Dreger of Northwestern University in Evanston, Illinois. She claims that researchers have misled an unknown number of pregnant women into taking the experimental treatment without properly informing them of its risks. Since the 1980s, Maria New of Mount Sinai School of Medicine in New York has studied and popularised the idea of prescribing dexamethasone "off-label" to women at risk of having foetuses with congenital adrenal hyperplasia (CAH). The treatment is now taught as standard practice in medical schools. But because the drug must be given very early in pregnancy before the fetus' gender or CAH status is known, many fetuses are treated unnecessarily. A child with two carrier parents has a one-in-four chance of having the disease, and the treatment only works for girls. There is little research available on the effects of dexamethasone, which mimics a steroid hormone. And because dexamethasone doesn't cure CAH but only prevents masculinisation of girls, it can be difficult to distinguish possible effects of the drug from other treatments the children receive after birth. © Copyright Reed Business Information Ltd.

Insulin may be Big Antler hormone

By Susan Milius OTTAWA — Some of the animal kingdom’s showiest extremes, from deer antlers to the outsized horn of the male rhinoceros beetle, may be natural insulin meters. As an animal grows, the nubbins of tissue that will form its big weapons or displays may be more sensitive to insulin than other developing body parts, Douglas Emlen of the University Montana said July 10 at the Evolution Ottawa scientific congress. The proposal “potentially narrows the range of explanations for the evolution of ornaments and weapons,” said Bob Montgomerie of Queen’s University in Kingston, Ontario, who studies courtship-related features in birds. Insulin orchestrates growth in tune with how much food a young animal gets, Emlen explained. A well-fed youngster flush with insulin will grow the most spectacular horns or other paraphernalia, while underfed rivals remain stunted. If the growing antlers or other extreme structures are supersensitive to insulin, they will supersize out of proportion to less sensitive tissue. That’s the case for the horns of the rhinoceros beetle, Trypoxylus dichotomus. Males of the species grow horns about two-thirds as long as the rest of their bodies. They use these fearsome weapons to knock rivals away from sap-oozing wounds on trees where females go to feed. The horns are eight times more responsive to insulin or insulin-like growth factors than some other body parts, Emlen said. That sensitivity fits with reports from other researchers that insulin or related signals affect development of antlers in red deer and the outsized male claws in a type of shrimp and one kind of crab. For those animals though, researchers haven’t yet explored how the weaponry tissues’ sensitivity compares with that of other body parts. © Society for Science & the Public 2000 - 2012

Testosterone drug use growing despite risks

Shannon Pettypiece Testosterone replacement has long been prescribed for men who suffer from abnormally low levels of the male sex hormone, but overuse can lead to infertility and can even speed the growth of prostate cancer. That hasn't stopped Michael Murray, a healthy 43-year-old home stager who works in New York and Chicago, from getting frequent testosterone injections to raise his energy level and give his bodybuilding regime a boost. "Am I making a deal with the devil? A little bit, but I have to think about my quality of life," Murray explains. "It is like I'm in my 20s again." In what may become one of the most sought-after lifestyle drugs since the introduction of Pfizer's Viagra 14 years ago, new testosterone drugs from Eli Lilly, Abbott Laboratories, and other drugmakers are hot. Prescriptions for testosterone replacement therapies have more than doubled since 2006 to 5.6 million last year, according to data compiled by Bloomberg. Sales are expected to triple to $5 billion by 2017, forecasts Global Industry Analysts. As many as 13.8 million men older than 45 in the United States have low levels of testosterone, according to a 2006 study in the International Journal of Clinical Practice. The male sex hormone begins to decline after age 30, and tends to drop about 1 percent each year. Lower-than-normal levels can lead to a loss of libido, a decrease in bone and muscle mass, and depression. © 2012 Hearst Communications Inc.

Related chapters from BN: Chapter 5: Hormones and the Brain; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 16789 - Posted: 05.14.2012

Hormones Help Tiny Sharks Glow

by Daniel Strain Sharks may be known as terrors of the sea, but in some cases they're more like night lights. That's because many deep-sea sharks, like the smalleye pygmy shark (Squaliolus aliae), can make their own light, glowing from tail to snout as a possible means of camouflage. Now, a new study shows how this predator, the world's smallest shark, powers its luminescence. Smalleye pygmy sharks aren't just petite—they grow no more than 22 centimeters long—they're also hard to find, says study co-author Julien Claes, a shark biologist at the Catholic University of Louvain in Belgium. These fish swim hundreds of meters below the water's surface in the Indian and western Pacific oceans. When scientists do manage to pull one of these animals up, they sometimes catch an odd sight: a blue glow coming mostly from the shark's belly. Claes co-authored a paper in 2009 that showed that a second group of luminescent sharks, called lantern sharks (Etmopterus spinax), trigger their own glow using two hormones common in many animals: melatonin and prolactin. But it wasn't clear if smalleye pygmy sharks and their close relatives relied on the same molecules. So Claes and his colleagues launched a second survey, collecting 27 pygmy sharks off the coast of Taiwan. To determine what controlled their unearthly glow, the researchers took patches of the fish's skin and soaked them in various chemicals known to cue luminescence in other species. They then recorded the resulting glow—often so faint that it was tricky to see at a distance even in a dark room—using a light detector. And sure enough, when Claes tried melatonin, which in people helps to control cycles of sleep and waking, voila! There was light. © 2010 American Association for the Advancement of Science.

Related chapters from BN: Chapter 5: Hormones and the Brain; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 10: Biological Rhythms and Sleep
Link ID: 16716 - Posted: 04.26.2012

Slight Genetic Variations Can Affect How Others See You

By Janelle Weaver A micrograph view of crystallized oxytocin. Image: Alfred Pasieka/Photo Researchers, Inc. When we meet new people, we assess their character by watching their gestures and facial expressions. Now a study in the Proceedings of the National Academy of Sciences USA suggests that those nonverbal cues are communicating the presence of a specific form of a gene that makes us more or less responsive to others’ needs. The gene determines which type of receptor a person has for the hormone oxytocin. Oxytocin has been implicated in a variety of positive traits, such as trust, empathy and generosity. The hormone is detected by our body’s cells via their oxytocin receptors. In a past study, psychologist Sarina Rodrigues Saturn of Oregon State University and her collaborators found that people who have a certain variation of the receptor gene are more empathetic than those with the alternative form of the gene. In the new study, Saturn and her team showed volunteers 20-second silent video clips of individuals who were listening to their romantic partner recount an upsetting experience. The study participants watched for nonverbal behaviors, such as head nods and smiles, and rated every individual on a number of character traits. Those with the form of the oxytocin receptor gene associated with empathy were judged by the volunteers as being more trustworthy, compassionate and kind than those with the alternative form of the gene. “These slight genetic variations do have a big impact on not only how you feel internally but also how people perceive you,” Saturn says, adding that impressions based on nonverbal cues can help individuals quickly choose compatible friends or romantic partners. © 2012 Scientific American,

Gamma-Knife Surgery Halts Growth of World’s Tallest Living Human

By Katherine Harmon Years of surgeries and medications were unable to stop Sultan Kosen’s runaway growth. In 2010 at age 27 and a height of 2.46 meters (eight feet, one inch), he became the world’s tallest living man, according to Guinness World Records. But he wasn’t done growing. Kosen had been diagnosed with a growth disorder at age 10 after doctors in his native Turkey found a tumor on his pituitary gland. The tumor triggered the gland to release too much growth hormone. As a result, he has suffered from both gigantism, a condition in which too much growth hormone is secreted during childhood, and acromegaly, a condition caused by too much growth hormone in adulthood. The tumor was technically benign, but it was lodged near the bottom of his brain, making it difficult to operate on. Thus ensconced, the tumor—along with Kosen’s whole body—continued to grow to dangerous proportions. sultan kosen uva surgery So in May 2010, doctors at the University of Virginia Medical Center put Kosen on new medication to limit growth hormone production. Perhaps more importantly, they were also able to perform gamma-knife radiosurgery on his hard-to-reach tumor. Guided by MRI, the doctors used this super-precise technique, which harnesses high-power gamma rays, to disable the tumor without having to do more dangerous invasive surgery. © 2012 Scientific American

Related chapters from BN: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 16529 - Posted: 03.17.2012

Low Doses of Hormonelike Chemicals May Have Big Effects

By Marla Cone and Environmental Health News That is a main finding of a report, three years in the making, published Wednesday by a team of 12 scientists who study hormone-altering chemicals. Dozens of substances that can mimic or block estrogen, testosterone and other hormones are found in the environment, the food supply and consumer products, including plastics, pesticides and cosmetics. One of the biggest, longest-lasting controversies about these chemicals is whether the tiny doses that most people are exposed to are harmful. In the new report, researchers led by Tufts University's Laura Vandenberg concluded after examining hundreds of studies that health effects "are remarkably common" when people or animals are exposed to low doses of endocrine-disrupting compounds. As examples, they provide evidence for several controversial chemicals, including bisphenol A, found in polycarbonate plastic, canned foods and paper receipts, and the pesticide atrazine, used in large volumes mainly on corn. The scientists concluded that scientific evidence "clearly indicates that low doses cannot be ignored." They cited evidence of a wide range of health effects in people – from fetuses to aging adults – including links to infertility, cardiovascular disease, obesity, cancer and other disorders. "Whether low doses of endocrine-disrupting compounds influence human disorders is no longer conjecture, as epidemiological studies show that environmental exposures are associated with human diseases and disabilities," they wrote. © 2012 Scientific American

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 8: Hormones and Sex
Link ID: 16524 - Posted: 03.17.2012

When is comfort most comforting? When you’ve got a specific Oxytocin gene!

By Scicurious Hi. In a few minutes I’d like you to stand up and give a short public speech to a judgmental group of people. The speech will be about the current national and international effects of Marbury v Madison, with particular focus on violations of interstate commerce. You have 15 minutes to prepare and the speech will have to be 15 minutes long. I hope you’ve done your research. Nervous yet? If you are, you’re not alone. Fear of public speaking (glossophobia, or just stage fright) is one of the most common fears in the Western world. But it’s ok. We’re going to have you sit with your loved one, who will be able to give you encouragement as you prepare. Do you feel a little bit better? I bet you do. But do you really, actually feel better? Does your body react to stress differently when you’ve got a loved one with you to help you out? It turns out that it might. At least, if you’ve got a specific kind of oxytocin receptor gene. Oxytocin gets a lot of press. And well it should. Recent findings on oxytocin have shown effects on trust, on generosity, on behaviors in austistic children even. Not to mention all the effects that oxytocin has on parental bonding and on your sex life. While many of these studies have looked at levels of circulating oxytocin, or the effects of giving oxytocin (usually as a nasal spray) on behavior, people have recently started to look at the other side of oxytocin: the oxytocin receptor. © 2011 Scientific American,

Testes Hit by Herbicides

By Tim Wall A review of 142 studies on the effects of the herbicide atrazine had bad news for testes. "Essentially, atrazine chemically castrates animals. When you look at a male exposed to atrazine, the testes are missing sperm," Tyrone Hayes of the University of California, Berkeley told Discovery News. The effects of atrazine on male development are consistent across all examined animals, found a study published by a team of 22 researchers from more than 60 nations in the Journal of Steroid Biochemistry and Molecular Biology. Mammals, reptiles, and fish were all affected, but amphibians caught the worst of it. In a study by Hayes, male African clawed frogs turned into females after exposure to atrazine, which kills weeds around the world in everything from corn fields to orchards. "And this is not at extremely high concentrations" said co-author of the review Val Beasley of the University of Illinois in a press release. "These are at concentrations that are found in the environment." Humans aren't spared the effects of atrazine, the world's second most common herbicide after glyphosate, Hayes said. Hayes pointed to studies correlating atrazine exposure to low sperm quality, birth defects, miscarriage, and breast cancer © 2011 Discovery Communications, LLC.

For Some, Psychiatric Trouble May Start in Thyroid

By HARRIET BROWN In patients with depression, anxiety and other psychiatric problems, doctors often find abnormal blood levels of thyroid hormone. Treating the problem, they have found, can lead to improvements in mood, memory and cognition. Now researchers are exploring a somewhat controversial link between minor, or subclinical, thyroid problems and some patients’ psychiatric difficulties. After reviewing the literature on subclinical hypothyroidism and mood, Dr. Russell Joffe, a psychiatrist at the North Shore-Long Island Jewish Health System, and colleagues recently concluded that treating the condition, which affects about 2 percent of Americans, could alleviate some patients’ psychiatric symptoms and might even prevent future cognitive decline. Patients with psychiatric symptoms, Dr. Joffe said, “tell us that given thyroid hormones, they get better.” The thyroid, a bow-tie-shaped gland that wraps around the trachea, produces two hormones: thyroxine, or T4, and triiodothyronine, known as T3. These hormones play a role in a surprising range of physical processes, from regulation of body temperature and heartbeat to cognitive functioning. Any number of things can cause the thyroid to malfunction, including exposure to radiation, too much or too little iodine in the diet, medications like lithium, and autoimmune disease. And the incidence of thyroid disease rises with age. Too much thyroid hormone (hyperthyroidism) speeds the metabolism, causing symptoms like sweating, palpitations, weight loss and anxiety. Too little (hypothyroidism) can cause physical fatigue, weight gain and sluggishness, as well as depression, inability to concentrate and memory problems. © 2011 The New York Times Company

Related chapters from BN: Chapter 5: Hormones and the Brain; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 16068 - Posted: 11.22.2011

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