Navigation Links
Males Lifespan Shortened By Elevated Levels Of Testosterone

According to a new research, men who have elevated levels of testosterone may be successful as far as progeny is concerned but may lead shorter lives// when compared with men who secrete normal level of the hormone.

According to foodconsumer.org, comparative studies have studied testosterone levels and related them to mating systems and aggression, but very few studies have attempted to relate testosterone to fitness, that is, the combination of lifetime reproductive success and survival, in the wild or experimentally. Over nine breeding seasons, Wendy Reed (North Dakota State University) and her colleagues followed a group of dark-eyed juncos, small mountain songbirds found throughout North America. They injected males with elevated levels of testosterone and found that they had shorter lives but that they were very successful at siring more offspring ? even with females who were mated with other males.

"The surprising result was that testosterone-treated males had a higher overall fitness than control males," write the authors in a study in the May issue of American Naturalist. This led to the question of why don't juncos naturally have higher levels of testosterone? Testosterone-treated males produced more offspring, but they were smaller, and smaller offspring had lower postfledging survival. Older, more experienced females preferred to mate with older males and realized higher reproductive success when they did so. While young males treated with testosterone increased their ability to attract older females, it resulted in poor reproductive performance.

"Although testosterone increased male fitness, as measured by lifespan and number of offspring, the extended effects on offspring and female mates were generally negative and may ultimately constrain the evolution of higher testosterone levels in males," conclude the authors.


'"/>




Page: 1

Related medicine news :

1. Males Show More Risky Behaviour with Alcohol
2. Impact Of Stress On Belfast Males
3. Sexually Abused Males Found Struggling In heir relations with Healthcare Providers
4. Same Genes Act Differently in Males and Females
5. Fewer Neurons in Amygdala of Autistic Males
6. Researchers Find Fewer Neurons in the Amygdala of Males with Autism
7. Males too Undergoes Hormonal Changes During Parenting: Study
8. Males Adapt To Battle With Competing Sperm
9. Sun Exposure Severe in Males
10. Cognitive Problems Occur More Rapidly in Female Alcoholics Than in Males
11. Female Ducks Develop Complicated Genitals to Outwit Aggressive Males
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... Apple ... care services, staged a mock evacuation of the facility as part of a disaster ... Fire Department, Echo Hose EMS and Shelton City Emergency Manager, as well as the ...
(Date:10/13/2017)... , ... October 13, 2017 , ... Global Healthcare Management’s ... Alexandria Park in Milford, NJ. This free event, sponsored by Global Healthcare Management’s ... The fun run is geared towards children of all ages; it is a ...
(Date:10/13/2017)... ... October 13, 2017 , ... “The Journey: From the ... danger possible to save lost souls in the Philippines. “The Journey: From the Mountains ... a dedicated teacher of the Bible. She has taught all ages and currently teaches ...
(Date:10/12/2017)... ... October 12, 2017 , ... Planet Fitness, one of the largest and ... plans to open a flagship location in Covington, LA at 401 N. U.S. Highway ... store next to Office Depot in the Holiday Square shopping center. Its location allows ...
(Date:10/12/2017)... ... 2017 , ... Asante, a nationally recognized health system in ... existing home health joint venture through an agreement, effective October 1, 2017, to ... home health company with Asante, delivering clinically integrated care, for the past eight ...
Breaking Medicine News(10 mins):
(Date:10/10/2017)... -- NDS received FDA 510(k) clearance in May 2017 for its highly ... designed for endoscopy environments. An innovative secondary monitor solution, ZeroWire ... support the improvement of patient outcomes, procedural efficiency, and the lowering ... ... ...
(Date:10/4/2017)... 4, 2017  South Korean-based healthcare product Development Company ... "cprCUBE" on Kickstarter. The device will educate the user ... with better efficiency compared to the dated and pricey ... on efficacy of the compression for a more informed ... goal to raise $5,000. ...
(Date:10/2/2017)... 2017  Eli Lilly and Company (NYSE: ... third quarter of 2017 on Tuesday, October 24, 2017. ... day with the investment community and media to further ... call will begin at 9 a.m. Eastern time. Investors, ... webcast of the conference call through a link that ...
Breaking Medicine Technology: