Links for Keyword: Hormones & Behavior

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By Helen Briggs Health editor, BBC News website The timing of when a girl reaches puberty is controlled by hundreds of genes, say scientists. And age at first period may vary in daughters from the same family because of genetic factors, research shows. The findings, published in Nature, could give clues to why early puberty may be linked to an increased risk of health conditions. Scientists at 166 institutions analysed the DNA of more than 180,000 women in one of the largest studies of its kind. They found that hundreds of genes were involved in the timing of puberty. Unusually, a girl's first period was also influenced by imprinted genes - a rare event where genes from either the mother of father are silenced. "Our findings imply that in a family, one parent may more profoundly affect puberty timing in their daughters than the other parent," said lead researcher Dr John Perry of the University of Cambridge. He said the biological complexity revealed in the study was "amazing". "We identified more than 100 regions of the genome associated with puberty timing, but our analysis suggests there are likely to be thousands," he told BBC News. Lifestyle BBC © 2014

Related chapters from BP7e: 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: 19879 - Posted: 07.26.2014

Virginia Morell If we humans inhale oxytocin, the so-called “love hormone,” we become more trusting, cooperative, and generous. Scientists have shown that it’s the key chemical in the formation of bonds between many mammalian species and their offspring. But does oxytocin play the same role in social relationships that aren’t about reproduction? To find out, scientists in Japan sprayed either oxytocin or a saline spray into the nostrils of 16 pet dogs, all more than 1 year old. The canines then joined their owners, who were seated in another room and didn’t know which treatment their pooch had received. The owners were instructed to ignore any social response from their dogs. But those Fidos that inhaled the oxytocin made it tough for their masters not to break the rule. A statistical analysis showed the canines were more likely to sniff, lick, and paw at their people than were those given the saline solution. The amount of time that the oxytocin-enhanced dogs spent close to their owners, staring at their eyes, was also markedly higher, the scientists report online today in the Proceedings of the National Academy of Sciences. Getting a whiff of oxytocin also made the dogs friendlier toward their dog pals as determined by the amount of time they spent in close proximity to their buddies. The study supports the idea, the scientists say, that oxytocin isn’t just produced in mammals during reproductive events. It’s also key to forming and maintaining close social relationships—even when those are with unrelated individuals or different species. © 2014 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 19716 - Posted: 06.10.2014

By NICHOLAS BAKALAR The hormone estrogen is the recommended treatment for menopausal night sweats and hot flashes, but some women are unable or unwilling to use it. Now a clinical trial suggests that the antidepressant venlafaxine, often used as an alternative, is equally effective. In an eight-week placebo-controlled double-blind study, researchers randomly assigned 339 perimenopausal and postmenopausal women to one of three treatments: 0.5 milligrams a day of estrogen (in the form of estradiol), 75 milligrams a day of the antidepressant venlafaxine (a generic form of Effexor), or a placebo. Before the start of the study, all the women had had symptoms at least 14 times a week. Compared to the rate before the study — an average of 8.1 episodes a day — the frequency of hot flashes and night sweats declined by 52.9 percent in the estradiol group, 47.6 percent in the Effexor group, and 28.6 percent among those who took a placebo. Both Effexor and estradiol were effective treatments, but the study, published online in JAMA Internal Medicine, was not large enough to show that one was significantly better than the other. “Women have important choices of different medications to discuss with their doctors,” said the lead author, Dr. Hadine Joffe, an associate professor of psychiatry at Harvard. “They should know, as they think about these options, that both are effective.” © 2014 The New York Times Company

Related chapters from BP7e: 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: Biological Basis of Behavioral Disorders
Link ID: 19673 - Posted: 05.31.2014

The hormone oxytocin appears to increase social behaviors in newborn rhesus monkeys, according to a study by researchers at the National Institutes of Health, the University of Parma in Italy, and the University of Massachusetts, Amherst. The findings indicate that oxytocin is a promising candidate for new treatments for developmental disorders affecting social skills and bonding. Oxytocin, a hormone produced by the pituitary gland, is involved in labor and birth and in the production of breast milk. Studies have shown that oxytocin also plays a role in parental bonding, mating, and in social dynamics. Because of its possible involvement in social encounters, many researchers have suggested that oxytocin might be useful as a treatment for conditions affecting social behaviors, such as autism spectrum disorders. Although oxytocin has been shown to increase certain social behaviors in adults, before the current study it had not been shown to do so in primate infants of any species. Working with infant rhesus monkeys, the NIH researchers found that oxytocin increased two facial gestures associated with social interactions— one used by the monkeys themselves in certain social situations, the other in imitation of their human caregivers. “It was important to test whether oxytocin would promote social behaviors in infants in the same respects as it appears to promote social interaction among adults,” said the study’s first author, Elizabeth A. Simpson, Ph.D., postdoctoral fellow of the University of Parma, conducting research in the Comparative Behavioral Genetics Section of the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. “Our results indicate that oxytocin is a candidate for further studies on treating developmental disorders of social functioning.” The study was published online in Proceedings of the National Academy of Sciences.

Related chapters from BP7e: 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: 19547 - Posted: 04.29.2014

By Karen Kaplan There are lies, damn lies – and the lies that we tell for the sake of others when we are under the influence of oxytocin. Researchers found that after a squirt of the so-called love hormone, volunteers lied more readily about their results in a game in order to benefit their team. Compared with control subjects who were given a placebo, those on oxytocin told more extreme lies and told them with less hesitation, according to a study published Monday in Proceedings of the National Academy of Sciences. Oxytocin is a brain hormone that is probably best known for its role in helping mothers bond with their newborns. In recent years, scientists have been examining its role in monogamy and in strengthening trust and empathy in social groups. Sometimes, doing what’s good for the group requires lying. (Think of parents who fake their addresses to get their kids into a better school.) A pair of researchers from Ben-Gurion University of the Negev in Israel and the University of Amsterdam figured that oxytocin would play a role in this type of behavior, so they set up a series of experiments to test their hypothesis. The researchers designed a simple computer game that asked players to predict whether a virtual coin toss would wind up heads or tails. After seeing the outcome on a computer screen, players were asked to report whether their prediction was correct or not. In some cases, making the right prediction would earn a player’s team a small payment (the equivalent of about 40 cents). In other cases, a correct prediction would cost the team the same amount, and sometimes there was no payoff or cost. Los Angeles Times Copyright 2014

Related chapters from BP7e: 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: 19434 - Posted: 04.01.2014

Ian Sample, science correspondent, in Chicago Researchers have found evidence – if evidence were needed – that men have less sex after becoming a father for the first time. A study of more than 400 young men in the Philippines found that their sex lives declined significantly when they had their first child. The fall in sexual activity was associated with the men's testosterone levels, which are known to fall when men start families, but the latest research shows that the greater the fall in testosterone, the less sex men reported. Lee Gettler, an anthropologist at the University of Notre Dame in Indiana, gathered medical and lifestyle information on the men from the ages of 21 to 26 years old and found there were physiological and behavioural changes as some of them married and had children. When men got married their testosterone levels fell, and declined even further when they had their first child. That led to the question of whether falling testosterone might impact on their sex lives. "I didn't think that testosterone would be linked to men's sexual behaviour, but when we tested it we found that as men transitioned to fatherhood, the more their testosterone declined the less frequently they reported having sex with their partner," Gettler said. "Does this mean that men who care for children have low testosterone and no sex? No, it has nothing to do with childcare." The impact on men's sex lives was not linked to the amount of time and energy they invested in childcare, he said. Gettler described his research at the annual meeting of the American Association for the Advancement of Science in Chicago. © 2014 Guardian News and Media Limited

Related chapters from BP7e: 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: 19250 - Posted: 02.15.2014

By JOHN LA PUMA SANTA BARBARA, Calif. — A FUNNY thing has happened in the United States over the last few decades. Men’s average testosterone levels have been dropping by at least 1 percent a year, according to a 2006 study in The Journal of Clinical Endocrinology and Metabolism. Testosterone appears to decline naturally with aging, but internal belly fat depresses the hormone further, especially in obese men. Drugs like steroids and opiates also lower testosterone, and it’s suspected that chemicals like bisphenol A (or BPA, commonly found in plastic food containers) and diseases like Type 2 diabetes play a role as well. Men feel the loss. Clinical testosterone deficiency, which is variously defined as lower than 220 to 350 nanograms of testosterone per deciliter of blood serum, can cause men to lose sex drive and fertility. Their bone density often declines, and they may feel tired and experience hot flashes and sweats. But “low T,” as the condition has been labeled, isn’t nearly as common as the drug ads for prescription testosterone would have you believe. Pharmaceutical companies have seized on the decline in testosterone levels as pathological and applicable to every man. They aim to convince men that common effects of aging like slowing down a bit and feeling less sexual actually constitute a new disease, and that they need a prescription to cure it. This is a seductive message for many men, who just want to feel better than they do, and want to give it a shot, literally. The problem is that prescription testosterone doesn’t just give your T level a boost: it may also increase your risk of heart attack. It can add huge numbers of red blood cells to your bloodstream and shrink your testes. In some men, it increases aggression and irritability. © 2014 The New York Times Company

Related chapters from BP7e: 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: 19238 - Posted: 02.11.2014

By RONI CARYN RABIN Nearly a decade ago, researchers in Boston decided to see whether older men who were not in very good shape could benefit from daily doses of testosterone. The scientists recruited several hundred volunteers and gave them the hormone or a placebo. Those taking testosterone got stronger, compared with those taking the placebo, and they could carry a load up stairs faster. But they also had nearly five times the number of cardiovascular problems, including heart attacks and strokes, and safety monitors ended the trial early. Since those findings were published in 2010, studies of testosterone treatment have produced mixed results. A 2012 study of veterans aged 40 and over with low testosterone found that those treated with the hormone were less likely to die, but more recent reports, including one published last week, have documented an increase in cardiovascular risk in men over age 65 taking testosterone, as well as in younger men with a history of heart disease. Officials at the Food and Drug Administration said on Friday that they were reassessing the safety of testosterone products in light of the recent studies, and will investigate rates of stroke, heart attack and death in men using the drugs. In recent years, testosterone has been heavily promoted as a cure-all for low energy, low libido, depression and other ills among middle-aged men. “Low T” is a ubiquitous diagnosis, heard in television commercials and locker rooms. Between 2001 and 2011, hormone use by men 40 and over nearly quadrupled. By the end of that period, nearly one in 25 men in their 60s was taking testosterone. Though the drug is indicated for men with abnormally low testosterone levels, a condition called hypogonadism, doctors have been prescribing it to many men with normal levels. © 2014 The New York Times Company

Related chapters from BP7e: 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: 19199 - Posted: 02.04.2014

// by Megan Gannon, Live Science News Editor Bonobos have a reputation among the great apes as "hippie chimps," and new research hints that high levels of a key thyroid hormone may play a role in keeping the animals' aggression in check. Found in the lowland forests of the Democratic Republic of the Congo, bonobos (Pan troglodytes) are closely related to chimpanzees (Pan troglodytes) but the two diverge in behavior. Bonobos seem to diffuse social tension with an impressive repertoire of sex acts rather than physical fights. Males in particular show low levels of aggression — they even maintain platonic friendships with females and stick by their mothers into adulthood. The life of male chimpanzees, meanwhile, revolves around climbing the social ladder (or at least hanging onto their current rung), and navigating cooperative and aggressive relationships with other males. [8 Humanlike Behaviors of Primates] Scientists recently found another big difference between the two Pan species: A key thyroid hormone decreases at a much later age in bonobos compared with chimps. For their study, scientists took urine samples from about 100 chimpanzees and 96 bonobos living in zoos. The researchers specifically looked at the apes' levels of triiodothyronine (T3), a hormone in the thyroid gland that is crucial for development in all vertebrates (animals with backbones). © 2013 Discovery Communications, LLC

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 19056 - Posted: 12.21.2013

A whiff of oxytocin may help love not fade away. Researchers asked 20 unmarried men in multiyear relationships to rank the attractiveness of pictures of their partner, acquaintances, and strangers. When the men received a nasal spray of oxytocin—which is released by the body during sexual arousal—they rated their partners more highly but not the other women. MRI scans show that after an oxytocin dose, areas of the brain associated with rewards, which also drive drug addiction, were more active when the men saw pictures of their partner, the researchers report online today in the Proceedings of the National Academy of Sciences. The finding could help explain the biological roots of monogamy in humans: Being in a long-term relationship raises a person's oxytocin levels, which in turn increase the psychological reward of spending more time with that person. The cycle, the team concluded, could literally lead to an addiction to one’s lover. © 2013 American Association for the Advancement of Science

Related chapters from BP7e: 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: 18971 - Posted: 11.26.2013

By MARY LOU JEPSEN IN my early 30s, for a few months, I altered my body chemistry and hormones so that I was closer to a man in his early 20s. I was blown away by how dramatically my thoughts changed. I was angry almost all the time, thought about sex constantly, and assumed I was the smartest person in the entire world. Over the years I had met guys rather like this. I was not experimenting with hormone levels out of idle curiosity or in some kind of quirky science experiment. I was on hormone treatments because I’d had a tumor removed along with part of my pituitary gland, which makes key hormones the body needs to function. This long journey may have started as early as 1978, when I was 13. I spent a summer in intensive care with an unknown disease. After that summer, I never thought I would live a long life. So I wanted to live, to do interesting, fascinating work in the limited time I thought I had left. I took on the math-intensive art form of holography, and in my early 20s traveled the world, living on university fellowships to pursue this esoteric craft. I didn’t date much, really — perhaps because I didn’t have many hormones, though I didn’t know that at the time. I worked as an artist, played in a band, met Andy Warhol, Christo, Lou Reed and David Byrne. I had fun. But the gravity of my illness grew in the 1990s. The growth that shut down my pituitary gland’s ability to produce hormones did so insidiously over many years. By my early 20s it was, I suspect in retrospect, causing misdiagnosis of symptoms that were most likely caused by lack of hormones like cortisol. No diagnosis was found, despite the efforts of many doctors. I was a doctoral student in electrical engineering at an Ivy League school, but was growing progressively worse. I routinely slept about 20 hours a day, lived with a constant blistering headache and frequent vomiting, and was periodically wheelchair-bound. Large sections of my skin cycled through a rainbow of colors and sores, half of my face wouldn’t move as if Novocain had been applied. I drooled. Worse: I felt stupid. I couldn’t subtract anymore. I couldn’t make a to-do list, let alone accomplish items on one. I recognized that I wasn’t capable of continuing in graduate school. Utterly defeated, I filled out the paperwork to drop out. © 2013 The New York Times Company

Related chapters from BP7e: 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: 18969 - Posted: 11.25.2013

By NATASHA SINGER One afternoon a few months ago, a 45-year-old sales representative named Mike called “The Dr. Harry Fisch Show,” a weekly men’s health program on the Howard Stern channel on Sirius XM Radio, where no male medical or sexual issue goes unexplored. “I feel like a 70-year-old man in a 45-year-old body,” Mike, from Vancouver, British Columbia, told Dr. Fisch on the live broadcast. “I want to feel good. I don’t want to feel tired all day.” A regular listener, Mike had heard Dr. Fisch, a Park Avenue urologist and fertility specialist, talk about a phenomenon called “low testosterone” or “low T.” Dr. Fisch likes to say that a man’s testosterone level is “the dipstick” of his health; he regularly appears on programs like “CBS This Morning” to talk about the malaise that may coincide with low testosterone. He is also the medical expert featured on IsItLowT.com, an informational website sponsored by AbbVie, the drug maker behind AndroGel, the best-selling prescription testosterone gel. Like many men who have seen that site or commercials or online quizzes about “low T,” Mike suspected that diminished testosterone was the cause of his lethargy. And he hoped, as the marketing campaigns seem to suggest, that taking a prescription testosterone drug would make him feel more energetic. “I took your advice and I went and got my testosterone checked,” Mike told Dr. Fisch. Mike’s own physician, he related, told him that his testosterone “was a little low” and prescribed a testosterone medication. Mike also said he had diabetes and high blood pressure and was 40 pounds overweight. Dr. Fisch explained that conditions like obesity might be accompanied by decreased testosterone and energy, and he urged Mike to exercise more and to lose weight. But if Mike had trouble overhauling his diet and exercise habits, Dr. Fisch said, taking testosterone might give him the boost he needed to do so. “If it gives you more energy to exercise,” Dr. Fisch said of the testosterone drug, “I’m all for it.” © 2013 The New York Times Company

Related chapters from BP7e: 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: 18968 - Posted: 11.25.2013

By Rahul K. Parikh, The message showed up on my desk one day while I was seeing a patient. Its choppy shorthand read: “Admits to injecting testosterone. Now decreased libido. Call back to discuss.” The caller was a 15-year-old lacrosse player who hadn’t been part of my practice long. Like many boys in his age group, he rarely came to the office. When I responded to his message later that afternoon, the young man carried his end of the conversation with the typical terseness of a teenager. “Where did you get the steroids?” I asked. “On the Internet.” “How long did you use them?” “A few months.” “And what are you experiencing now?” He told me his nipples were sore and swollen. “I’ve been more tired and moody as well.” My patient was experiencing classic side effects of steroid use. About 6 percent of teenagers admit to using performance-enhancing drugs, according to a recent survey, though it’s easy to assume that that number is low. How many teens would admit to using such drugs, even anonymously to a researcher? And yet here was one teen, forced by the drug’s side effect, having to make an embarrassing confession to me and his family. (Details of this case have been altered to protect patient privacy.) Despite my patient’s fear, I was confident that a young, healthy teenager who briefly used steroids would bounce back, though it might take some time — and patience — for his symptoms to dissipate. When I explained this to my patient, he told me that he wanted his testosterone level tested, to make sure there wasn’t something more seriously wrong. I got the sense that he thought there was some way I could magically undo the harm he had caused himself. I paused and considered his request, which came across more like an order. © 1996-2013 The Washington Post

Related chapters from BP7e: 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: 18947 - Posted: 11.20.2013

By ELISABETH ROSENTHAL The barrage of advertisements targets older men. “Have you noticed a recent deterioration of your ability to play sports?” “Do you have a decrease in sex drive?” “Do you have a lack of energy?” If so, the ads warn, you should “talk to your doctor about whether you have low testosterone” — “Low T,” as they put it. In the view of many physicians, that is in large part an invented condition. Last year, drug makers in the United States spent $3.47 billion on advertising directly to consumers, according to FiercePharma.com. And while ever-present ads like those from AbbVie Pharmaceuticals have buoyed sales of testosterone gels, that may be bad for patients as well as the United States’ $2.7 trillion annual health care bill, experts say. Sales of prescription testosterone gels that are absorbed through the skin generated over $2 billion in American sales last year, a number that is expected to more than double by 2017. Abbott Laboratories — which owned AbbVie until Jan. 1 — spent $80 million advertising its version, AndroGel, last year. Once a niche treatment for people suffering from hormonal deficiencies caused by medical problems like endocrine tumors or the disruptive effects of chemotherapy, the prescription gels are increasingly being sold as lifestyle products, to raise dipping levels of the male sex hormone as men age. “The market for testosterone gels evolved because there is an appetite among men and because there is advertising,” said Dr. Joel Finkelstein, an associate professor at Harvard Medical School who is studying male hormone changes with aging. “The problem is that no one has proved that it works and we don’t know the risks.” © 2013 The New York Times Company

Related chapters from BP7e: 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: 18790 - Posted: 10.16.2013

By DENISE GRADY Hormone therapy for menopause is one of the most divisive subjects in medicine, hailed by some as a boon to women’s comfort and well-being, vilified by others as a threat to health. A new analysis finds truth somewhere in the middle, reaffirming previous warnings that the drugs have more risks than benefits for most women — but also stating that the harms are low early in menopause and that hormones are “appropriate for symptom management in some women.” Dr. JoAnn E. Manson, the first author of the analysis and a professor of medicine at Harvard’s medical school, said in an interview that the findings “should not be used as a basis for denying women treatment if they’re in early menopause and have significant distressing symptoms.” The new report, published on Tuesday in The Journal of the American Medical Association, is based on long-term data from the Women’s Health Initiative, a large, federally funded study that turned medical thinking on its head a decade ago by uncovering the risks of hormones. The new report is the first to include extended follow-up data from the original health initiative study, an additional six to eight years’ worth of information on about 80 percent of the original participants. They took a combination of estrogen and progesterone, estrogen alone or placebos for several years. For combined hormones, for every 10,000 women taking the drugs, the new analysis found that there were six additional instances of heart problems, nine more strokes, nine more blood clots in the lungs and nine more cases of breast cancer. On the benefit side, there were six fewer cases of colorectal cancer, one fewer case of uterine cancer, six fewer hip fractures and one fewer death. Most of the effects wore off once the drugs were stopped, but the risk of breast cancer remained slightly elevated. © 2013 The New York Times Company

Related chapters from BP7e: Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 18733 - Posted: 10.02.2013

Mark Peplow Hormone-disrupting chemicals may be far more prevalent in lakes and rivers than previously thought. Environmental scientists have discovered that although these compounds are often broken down by sunlight, they can regenerate at night, returning to life like zombies. “The assumption is that if it’s gone, we don’t have to worry about it,” says environmental engineer Edward Kolodziej of the University of Nevada in Reno, joint leader of the study. “But we’re under-predicting their environmental persistence.” “Risk assessments have been built on the basis that light exposure is enough to break down these products,” adds Laura Vandenberg, an endocrinologist at the University of Massachusetts in Amherst who was not involved in the study. “This work undermines that idea completely.” Endocrine disruptors — pollutants that unbalance hormone systems — are known to harm fish, and there is growing evidence linking them to health problems in humans, including infertility and various cancers1. But pinpointing specific culprits from the vast array of trace chemicals in the environment has proved difficult. Indeed, concentrations of known endocrine disruptors in rivers often seem to be too low to explain harmful effects in aquatic wildlife, says Kolodziej. He and his colleague David Cwiertny, an environmental engineer at the University of Iowa in Iowa City, decided to find out whether the breakdown products of endocrine disruptors could be boosting their environmental impact. Their team focused on trenbolone acetate, a synthetic anabolic steroid used as a growth promoter in more than 20 million cattle in the United States each year (this practice is banned in the European Union). © 2013 Nature Publishing Group

Related chapters from BP7e: 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: 18711 - Posted: 09.28.2013

Oxytocin, the naturally occuring human hormone linked to bonding with a newborn and romantic partner, could also help improve mood after rejection, a laboratory study suggests. When scientists in Montreal gave 100 students either oxytocin or a placebo through a nose spray and then tried to snub them in a conversation, feelings of trust were higher in the hormone group. But the hormone had no effect among those who weren't emotionally charged up by the social rejection of having researchers posing as students disagree, interrupt or ignore them. "Instead of the traditional 'fight or flight' response to social conflict where people get revved up to respond to a challenge or run away from it, oxytocin may promote the 'tend and befriend' response where people reach out to others for support after a stressful event. That can, in turn, strengthen social bonds and may be a healthier way to cope," study author Mark Ellenbogen said in a release. For a decade, researchers have speculated that oxytocin, known as the love hormone, motivates people to seek out social support to respond to challenges and blunt the negative hit of stress. Ellenbogen's team said its study offers the first experimental support of the idea that oxytocin motivates us to strengthen social bonds during times of distress. © CBC 2013

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 5: The Sensorimotor System
Link ID: 18351 - Posted: 07.06.2013

A randomized clinical trial of estrogen therapy in younger postmenopausal women, aged 50–55, has found no long-term risk or benefit to cognitive function. The National Institutes of Health-supported study, reported in JAMA Internal Medicine on June 24, 2013, looked at women taking conjugated equine estrogens, the most common type of postmenopausal hormone therapy in the United States. The earlier Women’s Health Initiative Memory Study (WHIMS) linked the same type of hormone therapy to cognitive decline and dementia in older postmenopausal women. The new findings come from the Women’s Health Initiative Memory Study of Younger Women (WHIMSY) trial and were reported by Mark A. Espeland, Ph.D., Wake Forest School of Medicine, Winston-Salem, N.C., on behalf of the academic research centers involved in the study. The study was funded primarily by the National Institute on Aging (NIA), along with the National Heart, Lung, and Blood Institute (NHLBI), both components of the NIH. “The WHIMS study found that estrogen-based postmenopausal hormone therapy produced deficits in cognitive function and increased risk for dementia when prescribed to women 65 and older,” said NIA Director Richard J. Hodes, M.D. “Researchers leading the WHIMSY study wanted to expand on those results by exploring the possibility of a window of opportunity whereby hormone therapy might promote or preserve brain health when given to younger women.” “In contrast to findings in older postmenopausal women, this study tells women that taking these types of estrogen-based hormone therapies for a relatively short period of time in their early postmenopausal years may not put them at increased risk for cognitive decline over the long term,” said Susan Resnick, Ph.D., chief of the Laboratory of Behavioral Neuroscience, in NIA’s Intramural Research Program and a co-author of the study. “Further, it is important to note that we did not find any cognitive benefit after long-term follow-up.”

Related chapters from BP7e: 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: 18310 - Posted: 06.25.2013

By ANAHAD O'CONNOR The number of middle-aged men with prescriptions for testosterone is climbing rapidly, raising concerns that increasing numbers of men are abusing the powerful hormone to boost their libidos and feel younger, researchers reported on Monday. Testosterone replacement therapy is approved specifically for the treatment of abnormally low testosterone levels, a condition called hypogonadism. The hormone helps build muscle, reduce body fat and improve sex drive. But a study published in the journal JAMA Internal Medicine found that many men who get prescriptions for the hormone have no evidence of a deficiency at all. The new study is the largest of testosterone prescribing patterns to date, involving nearly 11 million men who were tracked through a large health insurer. The report showed that the number of older and middle-aged men prescribed the hormone has tripled since 2001. Men in their 40s represent the fastest-growing group of users. About half of men prescribed testosterone had a diagnosis of hypogonadism, and roughly 40 percent had erectile or sexual dysfunction. One third had a diagnosis of fatigue. The medical group that sets clinical guidelines for testosterone replacement therapy, the Endocrine Society, recommends treatment only in men who have unequivocally low testosterone levels. That finding requires a blood test. But the new report found that a quarter of men did not have their levels tested before they received the hormone. It was also unclear what proportion of men who did undergo testing actually had results showing a deficiency. Copyright 2013 The New York Times Company

Related chapters from BP7e: 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: 18228 - Posted: 06.04.2013

Jo Marchant People with genes that make it tough for them to engage socially with others seem to be better than average at hypnotizing themselves. A study published today in Psychoneuroendocrinology1 concludes that such individuals are particularly good at becoming absorbed in their own internal world, and might also be more susceptible to other distortions of reality. Psychologist Richard Bryant of the University of New South Wales in Sydney and his colleagues tested the hypnotizability of volunteers with different forms of the receptor for oxytocin, a hormone that increases trust and social bonding. (Oxytocin's association with emotional attachment also earned it the nickname of 'love hormone'.) Those with gene variants linked to social detachment and autism were found to be most susceptible to hypnosis. Hypnosis has intrigued scientists since the nineteenth-century physician James Braid used it to alleviate pain in a variety of medical conditions, but it has never been fully understood. Hypnotized people can undergo a range of unusual experiences, including amnesia, anaesthesia and the loss of the ability to move their limbs. But some individuals are more affected by hypnosis than others — and no one knows why. Hormones and hypnotism How susceptible someone is to persuasion is an important factor in how easily they can be hypnotized by someone else. Bryant and his colleagues have previously shown that spraying a shot of oxytocin up people’s noses makes them more hypnotizable, and more likely to engage in potentially embarrassing activities such as swearing or dancing at a hypnotist’s suggestion. © 2013 Nature Publishing Group,

Related chapters from BP7e: 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: 18052 - Posted: 04.20.2013