Effect of nicotine and nicotine metabolites on insulin secretion from rabbit pancreas pieces.

Abstract

The effects of nicotine and the nicotine metabolites cotinine and γ–(3-pyridyl)-γ-oxobutyric acid on insulin secretion from rabbit pancreas pieces were studied with a radioimmunological method. High concentrations of nicotine inhibited a glucose (3.0 mg/ml) induced insulin secretion, while lower concentrations stimulated the secretion. The stimulating effect of nicotine was also demonstrated in a lower glucose concentration (0.6 mg/ml). A high concentration of cotinine stimulated the glucose induced insulin secretion, while inhibitory effects of cotinine were not observed. In further experiments it was shown that nicotine was not metabolised in the pancreas in vitro, thus the effect of nicotine on insulin secretion is not due to cotinine formation. Both the stimulatory and the inhibitory effects of nicotine as well as the stimulatory effect of cotinine were blocked by both atropine and hexamethonium. γ-(3-pyridyl)-γ-oxobutyric acid had no effect on the glucose induced insulin secretion. Several possibilit...