Na, K-ATPase activity of the microsomal fraction of the rat brain exposed to insulin

The effect of insulin on the activity of Na, K-ATPase was studied in rat brain microsomes. Addition of insulin to the incubation medium in a dose of 0.18 U/ml coupled with strophanthine did not change the enzyme activity. The raising of the hormone dose to 0.36 U/ml was accompanied by inhibition of the enzyme activity. The incubation duration (10 and 30 min) did not influence the Na-pump. Preincubation of brain microsomes with insulin for 5 min significantly activated Na, K-ATPase. It has been thus demonstrated that insulin is capable of influencing the activity of Na, K-ATPase of rat brain microsomes in vitro. The effect obtained depends both on the dose of the hormone introduced into the incubation medium and the experimental conditions.