Actions of antifertility chemicals on Xenopus laevis spermatozoa in vitro

Abstract

A test system involving fertilization in vitro of Xenopus laevis gametes was developed to study the effects of various chemosterilants on toad spermatozoa. The subsequent development of fertilized eggs indicated that effective concentrations and times of exposure were considerably greater than those likely to be achieved with antifertility doses to rodents. Low concentrations of tretamine and ethyleneurea on Xenopus spermatozoa produced high yields of abnormal embryos, whereas other epididymal sterilants active in the rat (trimethylphosphate and α chlorhydrin) were ineffective in very high concentration. Differences between results in vitro and in vivo may be due to environmental variations or indicate an action by certain compounds on epididymal function in rodents rather than a direct action upon spermatozoa.