Differential spermatogenic response of mice to the induction of dominant-lethal mutations by n-propyl methane-sulfonate and isopropyl methanesulfonate

Abstract

n-Propyl methanesulfonate (PMS) and isopropyl methanesulfonate (iPMS) induce dominant-lethal mutations in mice. The responses of the various spermatogenic stages to the induction of dominant-lethal mutations differ markedly for PMS and iPMS. PMS induces a high frequency of dominant-lethal mutations in mouse spermatozoa and late spermatids and a low frequency in early spermatids. No dominant-lethal mutations are induced in spermatocytes. The gametogenic response to PMS is similar to that seen after treatment with ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS). In equimolar doses in mice the relative efficiencies of alkyl methanesulfonates in inducing dominant-lethal mutations in spermatozoa and spermatids are as follows: MMS > EMS > PMS. iPMS induces dominant-lethal mutations in all postspermatogonial stages. After injection of 200 mg/kg of iPMS the percentage of dominant-lethal mutations induced in spermatozoa, spermatids, and spermatocytes is above 75. The yield of induced dominant-lethal mutations after injection of 50 mg/kg of iPMS is low in spermatozoa, falls to the control level in early spermatids, but increases drastically in spermatocytes.