NEW YORK: Scientists have evolved a method to develop a non-hormonal male contraceptive that inhibits the development of sperm.
Biomedical researchers at the Population Council in New York have carried out tests on lab rats, which have shown that blocking connections to cells which nurture developing sperms makes the animals infertile temporarily.
They say that sperms are made in the body in a process called spermatogenesis in which sperms are helped in their growth by a group of cells called Sertoli cells. Theoretically, if the connection between these two types of cells is broken, it can result in infertility.
In the experiment in rats, the scientists used a recently developed molecule called Adjudin to separate the developing sperm from the Sertoli cells.
However, Adjudin is known to cause toxicity when used in high doses. But, the researchers say relatively low doses of the molecule have been found to have no obvious side effects.
They say Adjudin can be linked chemically to a hormone, called FSH, which acts in the testicles where sperm cells are made. When the FSH was made inactive, it would merely act as a carrier and not cause any effect itself and it delivered Adjudin to where it was needed, facilitating much lower doses. This process led to the developing sperm cells "fall off" before they reach maturity, leading to complete but temporary loss of fertility in the rats. The contraceptive effective waned and the rats regained the ability to produce normal levels of sperm once the drug was cleared from their bloodstream.
The researchers now want to find out whether the method can be effective and safe in humans. Senior team member of the research team at Population Council Yan Cheng says the drug still needs several years of animal testing before a human trial is conceivable.
The results of the trial have been published in the journal Nature Medicine.
Similar studies have been carried out by a research team led by Dr Dolores Mruk at the Centre For Biomedical Research in New York.
Scientists have not been able to develop a male contraceptive pill because a man naturally produces about 150 million sperm cells each day of his adult life. Some of the contraceptives for men, which are now being developed, are based on altering the levels of sex hormones circulating in the bloodstream in order to inhibit the natural state of male hyper-fertility.
Final clinical trials are now being carried out on a hormonal male pill based on progesterone, the female hormone that inhibits the formation of sperm, and testosterone, the male hormone added to it to counter the adverse effects of the former. However, this is not apparently appealing to men because of the fears of the progesterone's effect on masculinity.
