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:2/8/2016)... ... February 08, 2016 , ... Coast Dental has a new way to help ... Month and family dentist Yvonne Dorrian, DMD, is hosting a free seminar on Friday, ... next to Target at 1207 North Peachtree Parkway in Peachtree City. Dr. Dorrian will ...
(Date:2/8/2016)... ... ... who has struggled to quit smoking, a man who has struggled with hair loss – ... his problems – and he did. Now Nabat, a serial entrepreneur featured as the October ... to the world and better people's lives. His own experience with nicotine addiction led to ...
(Date:2/8/2016)... ... February 08, 2016 , ... Tingley Rubber Corporation , ... provide its range of unique and advantaged protective solutions to a growing ... provide bilingual customer service and marketing support. A new distribution center in Brampton, ...
(Date:2/8/2016)... ... 08, 2016 , ... Local insurance agency Dennis Fuller & ... has initiated a fundraiser for a two year old little girl named Bella, ... To support this beautiful child who is facing life’s journey without her loving ...
(Date:2/8/2016)... ... , ... Remember the old saying “rub some dirt on it”? Perhaps you ... “Calcium Bentonite Clay” the health benefits of integrating clay into a daily diet are ... A former motivational speaker, Perry A~ has since dedicated her life to learning about ...
Breaking Medicine News(10 mins):
(Date:2/8/2016)... , Feb. 8, 2016  Ventana Medical ... that hundreds of the world,s top oncologists, pathologists, ... at the 12 th annual Tucson Symposium ... evolving theories and new outcomes in cancer research ... patients, lives. Thomas Grogan , annually ...
(Date:2/8/2016)... 2016 Nueterra, the nation,s largest ... the development of equity partnerships and focused ... divided its interests between two new companies—NueHealth ... continue the founding company,s private equity investment ... national system of integrated provider networks that ...
(Date:2/8/2016)... , Feb. 8, 2016 ... "Knee Reconstruction Devices Market by Product Type ... and Geography (U.S., Canada, Eu-5, Japan, Bric, Turkey, ... report to their offering. --> ... the "Knee Reconstruction Devices Market by Product ...
Breaking Medicine Technology: