Insulin effects on gastric secretion and blood electrolytes modified by injected potassium

In the intact gastric fistula dog, insulin has been shown to have several, probably independent, actions: 1. Hypoglycemia occurs, resulting in stimulation via the vagus of gastric electrolyte and pepsin secretion. 2. Plasma K+ levels fall and there is a transfer of Na from cells to plasma which is mainly K-dependent. 3. Another, and less clearly defined, effect on K+ results in inhibition of gastric electrolyte secretion and is rapidly reversed by injected K. This latter action is best explained by postulating an insulin-induced redistribution of K+ in cells with resulting depletion of cation site essential for electrolyte secretion. 4. The smooth muscle of the spleen contracts; this contraction can be only partly prevented by K injectin.