Characteristics of decrease of plasma gastrin by glucagon in man.

Abstract

Exogenously administered glucagon causes a decrease of plasma gastrin concentration, but the mechanism has not been fully elucidated. We measured antral gastrin concentrations and plasma gastrin levels before and during glucagon infusion in nine patients free of gastrointestinal diseases. In addition, we measured plasma gastrin levels in both the renal artery and renal vein in six patients with normal renal function before and during glucagon infusion. Glucagon caused a significant increase of antral gastrin concentration concomitant with a significant decrease of plasma gastrin level and a significant decrease of percent extraction of gastrin in the kidney. These observations suggest that glucagon causes the decrease of plasma gastrin level by inhibiting the release of gastrin from the antrum, but not by accelerating the renal extraction of gastrin.-antral gastrin concentration; renal extraction; glucagon Exogenous administration of glucagon causes a decrease of basal or postprandial plasma gastrin concentration (Becker et al. 1973;Hansky et al. 1973), as well as of gastric acid secretion in man (Dreiling and Janowitz 1959;Solomon and Spiro 1959;Dotevall and Westling 1960;Cohen et al. 1960;Konturek et al. 1975;Christiansen et al. 1976). The mechanism of the inhibitory effect of glucagon on acid secretion could be, at least in part, due to decreasing plasma gastrin concentration (Christiansen et al. 1976). However, the mechanism of the decrease of plasma gastrin concentration by glucagon in man has not been fully elucidated.Possible mechanisms concerning the diminution of plasma gastrin concentration by glucagon are that glucagon inhibits gastrin synthesis, or inhibits gastrin release, or accelerates gastrin metabolism. The decrease of postprandial gastrin concentration by glucagon suggests that glucagon inhibits gastrin release. On the other hand, the possibility that glucagon accelerates renal extraction of