Amylin is a peptide secreted from the pancreatic β-cell along with insulin in response
to nutrient stimuli. Amylin has been reported to delay gastric emptying, inhibit glucagon
secretion and gastric acid secretion, 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 intravenous infusions at varied
rates. Amylin significantly increased urine flow at an infusion rate resulting in
a plasma concentration of ∼ 52 pM, and at a concentration of ∼ 193 pM, it increased
sodium excretion, glomerular filtration rate and renal plasma flow. Renal calcium
and potassium excretion were significantly elevated at plasma amylin concentrations
of ∼ 52 pM and ∼ 193 pM, respectively. Higher concentrations of plasma amylin decreased
plasma calcium 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 occurred only at plasma concentrations
above the normal range, but within the range of concentrations reported in insulin
resistant rats.
Key words
Amylin - Renal function - Diuresis - Natriuresis
