Incidence of non-specific esterase during cleavage of rat ovum

Abstract

For the study of non-specific esterase on electron microscopic level the method with incubation medium described by Hanker et al. (1972) and modified by Trávník (1977) was used. The object of the study was the 1-,2-,4-,8-cell rat ovum, early and late blastocyst. To differentiate organophosphate sensitive and organophosphate resistant esterases, inhibition by means of diethyl-p-nitrophenyl phosphate (E 600) was used in the concentration of 10μ mol/1. As substrates thionaphthylacetate (TNA) at pH 7 and thioacetoxybenzanilide (TAB) at pH 5.6 were used.Distinct activity of organophosphate sensitive esterase has been proved in aggregations of vesicles and tubules of smooth endoplasmic reticulum (Fig. 1). In the course of cleavage the total organophosphate sensitive activity is reduced together with the decrease in the amount of the smooth endoplasmic reticulum. In our opinion the aggregations of vesicles of smooth endoplasmic reticulum represent the site of reserve of hydrolytic enzymes synthetized during oogenesis, as a similar trend has been observed also in acid and alkaline phosphatases (astná 1977, 1978).