A contraceptive drug for men , based on a non hormonal approach is being studied by scientists. Until now , the fact that an adult male usually produces 150 million sperm has made the formulation of a male birth control pill diffcult.
Final clinical trials are being done on a hormonal male pill , based on progesterone - a female hormone that inhibits the formation of sperm - and testosterone, the male hormone added to counter the adverse effects of progesterone. But this does not appeal to most men who have fears of the progesterone affecting their masculinity , in spite of lack of evidence of such a likelihood.
Chuen Yan Cheng of the Population Council in New York is pioneering a new approach to get around this problem . This method involves a a chemical called adherin which blocks the development of sperm temporarily , and does not alter the sex hormone ratio in the body. Studies on rats have also shown that there are no serious side effects on the heart, kidney, lungs and other vital organs in the long term.
During spermatogenesis when sperms are being manufactured in the testes, they are helped in their development into mature sperm by special tissue called Sertoli cells. Adherin acts by breaking the bond between the immature sperm and the Sertoli cells. Therefore the male hormones are not affected at all.
Adherin is toxic on its own in high doses. By binding it with a synthetic follicle stimulating hormone( FSH), which attaches itself only to the Sertoli cell, scientists could use much lower doses. The results of a study in rats showed that sperm production decreased , resulting in complete infertility. The rats started producing normal amounts of sperm once the drug had been eliminated from their blood stream, so the infertility is reversible.
This factor, Dr.Cheng feels, would set people's mind at rest, so they would be more willing to use the drug. A lot of work remains to be done before these findings can be used safely and effectively in humans .The drug would most likely have to be used as an implant in men as it breaks down in the digestive tract.
Similar studies have been done by a research team led by Dr Dolores Mruk, from the Centre For Biomedical Research in New York. Dr Richard Anderson, from the University of Edinburgh, who has been involved in the hormonal contraception research in the UK, says that these findings are promising , and could lead to an attractive option.