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Hormone strategy eyed for male contraceptive
NEW YORK (Reuters Health) - An effective hormonal contraceptive for men may be on the horizon, a new study suggests.
Daily application of a testosterone gel plus injections of a progesterone called DMPA every three months nearly completely suppresses sperm production in men, researchers at the University of Washington in Seattle report.
Dr. Stephanie T. Page and colleagues studied the effect of topical application of testosterone gel and long-lasting DMPA injections in 44 healthy men between the ages of 18 and 55. Some of the volunteers were also given acyline, a potent suppressor of testosterone production, every two weeks.
During the 24-week trial, the men provided semen samples every two weeks and monthly examinations were conducted for 36 weeks.
"All men had dramatic suppression of spermatogenesis," or sperm production, Page and her colleagues report in the Journal of Clinical Endocrinology and Metabolism. The addition of acyline did not appear to suppress spermatogenesis further.
"To date, side effect profiles with long-term testosterone gel use have not revealed any problems," Page told Reuters Health. However, the long-term effects are not known, and "clearly this will require further, long-term evaluation, similar to what we have learned from long-term studies of female hormonal contraceptives."
For example, "the lipid effects we found in this study were very minimal, but the impact of any change in serum lipids over many years could be important."
Another concern with long-term use of testosterone is its possible effects on the prostate. "We saw no changes in markers of prostate health in this study (but) only long-term studies that include many men can possibly address this issue," Page noted.
While the testosterone gel plus DMPA combination shows theoretical efficacy, "this was not a true efficacy study since we used sperm counts, not pregnancy, as an endpoint," she cautioned. "
SOURCE: Journal of Clinical Endocrinology and Metabolism, November 2006.
Reuters Health