The antifertility effects of a number of simple alkane sulphonic esters have been examined in the male rat by a combination of serial mating of treated animals and histological examination of the testes. The results are compared and contrasted with those obtained with Busulphan (Myleran), dimethylmyleran and various derivatives of ethyleneimine.
A spectrum of results on various stages of spermatogenesis has been obtained, which is difficult to reconcile with a common mode of action due to alkylation of cellular materials.
Certain simple esters produce strikingly different effects. Thus, methylethanesulphonate and methylmethanesulphonate cause early sterility due to interference with spermatids and spermatozoa. Isopropyl alkane sulphonates, on the other hand, cause sterility only after a delay of several weeks.
These esters are effective by mouth and their action is cumulative. Methylmethanesulphonate and methylethanesulphonate in small daily doses produce predictable periods of sterility, according to the dose rate given, which are completely reversible. There is no indication of any action on libido, nor evidence so far of toxic effects from these courses of treatment.
With the series of compounds examined, it has been possible to move the focus of drug action from spermatogonia to spermatids and spermatozoa with reduction of side effects. It is concluded that this work demonstrates that selective interference with fertility in the male is a distinct possibility.
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