L-dopa stimulation of glucagon secretion in man.

Abstract

ALTHOUGH orally administered L-dopa induces the release of plasma growth hormone and elevates plasma glucose levels in man,1 , 2 its effect on plasma glucagon has not been determined. We have recently reported that after a rapid intravenous injection of 10 mg per kilogram of L-dopa in the rhesus monkey, a prompt and statistically significant increase of plasma glucagon occurred, preceding the increase in plasma growth hormone.3 This finding is consistent with the following observations: L-dopa is a precursor in catecholamine biosynthesis4; electrical stimulation of the autonomic nerves innervating the pancreas of the dog results in augmented pancreatoduodenal-vein glucagon output5; . . .