EFFECTS OF RAT AMYLIN ON RENAL-FUNCTION IN THE RAT

Amylin is a peptide secreted from the pancreatic p-cell along with ins ulin in response to nutrient stimuli. Amylin has been reported to dela y gastric emptying, inhibit glucagon secretion and gastric acid secret ion, increase plasma lactate, plasma glucose and plasma renin activity , and decrease plasma calcium. Receptors for amylin have been found in the rat nucleus accumbens and the kidney. In the present experiments, amylin was administered to anesthetized rats by continuous intravenou s infusions at varied rates. Amylin significantly increased urine flow at an infusion rate resulting in a plasma concentration of similar to 52 pM, and at a concentration of similar to 193 pM, it increased sodi um excretion, glomerular filtration rate and renal plasma flow. Renal calcium and potassium excretion were significantly elevated at plasma amylin concentrations of similar to 52 pM and similar to 193 pM, respe ctively. Higher concentrations of plasma amylin decreased plasma calci um and potassium and blunted urinary excretion of these electrolytes. Thus, of the renal responses tested, diuresis and natriuresis appeared to be the most sensitive to infused amylin. These renal effects occur red only at plasma concentrations above the normal range, but within t he range of concentrations reported in insulin resistant rats.