Characteristics of decrease of plasma gastrin by glucagon in man.

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.