[Proteolytic activity in unfertilized eggs and embryos of the loach under the effect of insulin].

The paper deals with studies in proteolytic activity of loach eggs and embryos incubated in water and in insulin solutions. It is established that after fertilization the above-mentioned activity level increased considerably, but even at the cleavage stage of embryo development it is 7-10 times as low as in the liver and 3-5 times as low as in the skeletal muscle tissue of the adults. After incubation of unfertilized eggs in insulin solutions at relatively low concentrations (0.1 and 1.0 micro/ml) proteolytic activity of their extracts at the acid and alkaline pH values increased. At higher hormone concentrations (2.0 and 4.0 micro/ml) the level of this activity, on the contrary, decreased. Analogous changes in proteolytic activity were observed in embryos which were incubated in insulin solution up to the cleavage stage of development. However in this case the increase in the activity under the effect of lower hormone concentrations was observed only at the acid pH zone. Higher insulin concentrations at the blastula stage of embryo development exerted their inhibitory influence on proteolytic activity at the acid and neutral pH values.