There have been a couple of articles in the news of late on testosterone, a couple on health issues and one on the power of T in men to attract female partners (probably male partners, too, but that's not what they were looking for in the study).
We'll start with the fun one - higher T levels corresponded with more assertive mating behaviors, which resulted in higher attractiveness ratings from mating targets (you know, women):
Pre-competition testosterone levels were positively associated with men's dominance behaviors in the mate competition-including how assertive they were and how much they "took control" of the conversation-and with how much the woman indicated that she "clicked" with each of the men.Here's the original study reference:
R. B. Slatcher, P. H. Mehta, R. A. Josephs. Testosterone and Self-Reported Dominance Interact to Influence Human Mating Behavior. Social Psychological and Personality Science, 2011; DOI: 10.1177/1948550611400099
Testosterone Linked to Men's Ability to 'Woo' Potential MatesScienceDaily (Mar. 13, 2011) — Theories have long proposed that testosterone influences competition among males trying to attract females. Findings from a recent study at Wayne State University give a clearer understanding of the links between testosterone and human mating behavior, and how testosterone is associated with dominance and competitive success when men battle for the attention of an attractive woman.
The study engaged pairs of men in a seven-minute videotaped competition for the attention of an attractive female undergraduate. Pre-competition testosterone levels were positively associated with men's dominance behaviors in the mate competition-including how assertive they were and how much they "took control" of the conversation-and with how much the woman indicated that she "clicked" with each of the men.
According to Richard Slatcher, Ph.D., assistant professor of psychology in WSU's College of Liberal Arts and Sciences and a resident of Birmingham, Mich., the effects of testosterone on dominance behaviors were especially pronounced among men who reported having a high need for social dominance. In his study, "Testosterone and Self-Reported Dominance Interact to Influence Human Mating Behavior," published online Feb. 28 in the journal, Social Psychological and Personality Science, these men showed a strong positive association between their own testosterone and their own dominance behaviors and, most surprisingly, a strong negative association between their own testosterone and their opponents' dominance behaviors. In other words, men both high in testosterone and who reported a high need for social dominance appeared to be able somehow suppress their competitors' ability to attract potential mates. However, when men reported low need for dominance, there was no association between testosterone and dominance behaviors-either their own or their competitors'.
"We found that testosterone levels influenced men's dominance behaviors during the competitions, how much they derogated (or 'bashed') their competitors afterward, and how much the woman said she 'clicked' with them," said Slatcher. "Books, film and television often portray men who are bold and self-assured with women as being high in testosterone. Our results suggest that there is a kernel of truth to this stereotype, that naturally circulating testosterone indeed is associated with men's behaviors when they try to woo women."
Although many animal studies have shown that testosterone is associated with dominance when males compete for mates, none-until now-have demonstrated this association in humans.
"These findings highlight an important difference between humans and animals," said Slatcher. "In humans-unlike animals-explicit, conscious motives can affect how a hormone such as testosterone shapes behavior. Our findings indicate that testosterone is associated with dominance behaviors and success when men compete for the attention of an attractive woman, particularly when men also have a strong conscious desire for social dominance."
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OK, this stuff is a little more serious. But we'll start with the good news - testosterone replacement therapy does not seem to pose an increased risk of prostate cancer, which is what I have been saying all along.
From Renal & Urology News:
Testosterone Therapy Safe for the Prostate
Jody A. Charnow
March 20, 2011
Michael Zitzmann, MDVIENNA—Testosterone replacement therapy benefits hypogonadal men without adversely affecting prostate safety, according to the largest international trial of hypogonadal men receiving the treatment.
In the trial, 1,438 hypogonadal men received 6,333 injections of injectable, long-acting testosterone undeconoate (TU) during 1,103 patient-years. Patients received up to five TU injections over nine to 12 months. Study results, presented by Michael Zitzmann, MD, Professor of Medicine at the University of Muenster in Muenster, Germany, at the 26th Annual Congress of the European Association of Urology, demonstrated that the treatment improves erectile dysfunction and mental and sexual satisfaction without significantly impacting PSA levels. During the study, Dr. Zitzmann and his colleagues observed no case of prostate cancer.
“Testosterone replacement in hypogonadal men is a safe and highly effective medical procedure regarding multiple aspects of a man's life,” Dr. Zitzmann told Renal & Urology News.
Read the whole article.
OK, more good news - a new angle on prostate cancer research suggests that it's not testosterone at cause for enlarged prostates, or at least not in normal levels in normal people. Rather, it seems there is a hydraulics problem - a valve that allows pure testosterone to flow directly into the prostate.
This also comes from Renal & Urology News:
Mystery of Prostate Diseases Possibly Unraveled
March 22, 2011VIENNA—Benign prostatic hyperplasia (BPH) and prostate cancer could be the result a previously unrecognized route of free testosterone flow from the testes to the prostate, according to investigators.
The underlying cause, they say, is varicocele, which in turn is the result of a malfunction of one-way valves in the testicular venous drainage system, a phenomenon that exists only in humans.
“The evolution of prostate diseases is a long-standing enigma in medicine,” said lead investigator Yigal Gat, MSc, MD, PhD, Head of Andrology & Interventional Radiology at the Maayanei Hayeshua Medical Center in Bnei Brak, Israel, and a research consultant in Condensed Matter Physics, Sub-Micron Research, Weizmann Institute of Science in Rehovot, Israel. “Our research group has been working together for several years and via physical understanding we have come to the conclusion that did not surprise us - prostatic enlargement is actually a secondary symptom of a hitherto disregarded clinical problem—varicocele – namely, malfunction of those valves.”
Dr. Gat and his colleagues demonstrated that testosterone at a concentration of about 130 times that of physiologic levels reaches the prostate via the testicular and prostate venous drainage systems, causing accelerated proliferation of prostate cells.
I don't know how this study will play out in the cancer community - I've asked my friend at the U of A cancer center for her opinion.
Finally, as reported in Endocrine Today, 6 months of T replacement in elderly, "fragile" men produced improvements in function and strength, but that those improvements disappeared within the 6 months following the therapy. It seems the take-home on that is that for the therapy to be effective, it much be continued - it's not a short-term fix. On the other hand, there also were no problematic side effects (enlarged prostate, cholesterol increases, etc.).
Testosterone treatment in frail, elderly men lost effect after 6 months
O’Connell MD. J Clin Endocrinol Metab. 2011;96:454-458.
The effects of 6 months of testosterone therapy on muscle strength, lean body mass and quality of life in frail men were not sustained after the treatment period, researchers found.Using a single center, randomized, double blind, placebo-controlled trial, researchers in Britain assessed the androgen effects of testosterone in frail and intermediate-frail men. Testosterone is among the first wave of pharmacologic anabolic interventions in frail men for whom resistance training is not practical.
The study included 274 men, aged 65 to 90 years, with low testosterone levels (≤12 nmol/L or calculated free testosterone ≤250 pmol/L) and at least one criteria for frailty (exhaustion, weight loss, physical activity, walk time, grip strength). Participants were randomly assigned testosterone gel (25 mg to 75 mg per day) or placebo for 6 months.
In the testosterone-treated group, the mean testosterone level increased from 11.1 nmol/L at baseline to 18.4 nmol/L at 6 months, before decreasing to 10.5 nmol/L at 12 months. The adjusted mean difference between isometric knee extension peak torque in the testosterone-treated group and the placebo group was 8.1 Newton meters (95% CI, –0.2 to 16.5) at 6 months.
Lean body mass increased in the testosterone-treated arm, for a difference between the two groups of 1.2 kg (95% CI, 0.8-1.7) at 6 months. The treatment group showed improvement in sexual and somatic symptoms; prostate-specific antigen and hematocrit levels increased slightly in the treatment group. No differences between groups remained at 12 months.
The decline in muscle mass and strength after testosterone treatment for 6 months may not sufficiently interrupt the progression of frailty in the study’s cohort of intermediate-frail and frail elderly men, researchers wrote.
“The main finding of this study was that the increased [lean body mass], muscle strength and [quality of life] after 6-month [testosterone] treatment in intermediate-frail and frail elderly men were not maintained 6 months posttreatment. Our results also indicate that any potentially adverse changes in safety parameters of [testosterone] treatment did not persist posttreatment,” researchers concluded.
There you go - the latest news on our favorite hormone.
For more info:- Low Testosterone and Heart Failure Mortality (2011)
- Low Testosterone Could Kill You: Low Levels of Male Hormone May be More Dangerous Than Previously Thought (2007)
- Mortality Rate Increased Due To Low Testosterone Levels In Men (2011)
- Experts skeptical about testosterone for "male menopause" (2010)
1 comment:
Hi there! I have read some articles that states heart disease drug can help solve prostate cancer problem. Is it true? Wouldn't it be harmful for men who don't have heart disease to take the said drug? Thanks!
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