Effect of Epinephrine and Insulin on Tissue Electrolytes in Normal and Demedullated Rats

Abstract

The effect of epinephrine and insulin admn. on the water and ionic content of plasma, skeletal muscle, and liver was compared in normal sham-operated and adrenal demedullated (21 days after surgery) rats. Histological evidence was presented that the regenerated adrenal cortices appeared normal and medullary tissue was absent. A significant reduction in plasma and muscle K concn. was determined 1 hr. after epinephrine admn. in the sham and demedullated groups. A decreased plasma K level 1 hr. after insulin admn. was found in the sham group but not in the demedullated group. However, a significant increase in the plasma Na concn. after insulin was detd. in both sham and demedullated groups. Thus, the apparent effect of insulin upon the plasma K level in the intact animal was the resultant of "reflexly-elicited" epinephrine secretion following insulin-induced hypoglycemia and not the effect of insulin per se.