Doctors have long known that men with low testosterone are at greater risk for developing type 2 diabetes. For the first time, researchers have identified how testosterone helps men regulate blood sugar by triggering key signaling mechanisms in islets, clusters of cells within the pancreas that produce insulin. The findings, co-authored by Tulane University researchers, were published recently in the medical journal Cell Metabolism.
The study could help identify new treatments for type 2 diabetes in the large number of men with low testosterone due to age or prostate-cancer therapies.
Researchers used specially bred male mice that had insulin-producing cells with no androgen receptors. (The cell could not respond to the actions of testosterone.) The mice were fed a Western diet rich in fats and sugar and then the researchers tested their response to glucose. These special mice had lower insulin secretion and higher blood glucose compared with normal mice in the control group.
To better understand how testosterone interacts with insulin production within the pancreas, researchers administered testosterone and glucose directly to human insulin-producing (islet) cells treated with a substance to block the androgen receptor. They did the same to insulin-producing cells harvested from mice without androgen receptors.In both cases,the normal islet cells showed decreased insulin production compared with islet cells.
“We have found the cause — and a potential treatment pathway — for type 2 diabetes in testosterone-deficient men,” says senior author Franck Mauvais-Jarvis, M.D., a professor in the Department of Medicine at Tulane University School of Medicine. “Our study shows that testosterone is an anti-diabetic hormone in men. If we can modulate its action without side effects, it is a therapeutic avenue for type 2 diabetes.”
Source: Tulane University School of Medicine