Antifertility effects of some sulphonamides and related compounds and their accumulation in the epididymides of male rats

Nineteen sulphonamides and related drugs were screened for their antifertility effects in male rats. They were suspended in corn oil and fed orally to rats at 10 times the human dose for a period of 6 months. Of the 19 compounds tested, sulphamethazine, sulphapyridine, dapsone, sulphamethoxypyridazine, sulphaguanidine, sulphathizole, sulphamerazine and sulphadimethoxine reduced fecundity of male rats to 34.3, 37.6, 38.3, 53.6, 55.6, 58, 75 and 78.6% of control, respectively. The fall in fecundity was due to a reduction in the number of embryos compared with the number of corpora lutea per pregnant female, and, in some cases, was associated with a fall in epididymal sperm concentration and motility. Some of these compounds accumulated in the cauda epididymidis at concentrations equal to or higher than the free drug concentrations in the blood. It is proposed that the antifertility effects of some of these compounds may in part be mediated through a direct effect on epididymal stored spermatozoa, hence compromising some processes vital for fertilization.