GLUCAGON AND ALANINE-INDUCED INCREASES OF THE CANINE RENAL GLOMERULAR FILTRATION RATE

¹ College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, U.S.A.

Renal responses to intravenous DL-alanine (ala) and glucagon (GLN) infusions were compared in conscious dogs. Doses of GLN (0·1 µg/min) that did not increase plasma glucose (PG) concentrations, a physiological effect of GLN, stimulated glomerular filtration rate (G.F.R.). Higher GLN infusion rates (1·0 and 10·0 µg/min) stimulated G.F.R., renal plasma flow (R.P.F.), PG, and potassium and urea clearances. Ala infusions (1·3 mmol/min) had similar effects if the dogs had been pre-conditioned by feeding of corn starch, but not if they had been fed a normal diet. This level of ala infusion increased plasma a amino nitrogen to levels equivalent to plasma ala levels reported to stimulate GLN secretion. The reason for the lack of responsiveness to ala infusion when the normal diet was fed was not clear. When somatostatin (3·8, µg/min), an inhibitor of GLN secretion, and ala were infused simultaneously, G.F.R. was lower than when ala alone was infused. The data suggested that the ala-induced renal effects were mediated by GLN.