Renal extraction of endogenous gastrin in patients with normal renal function.

Renal extraction of gastrin in patients with normal clearance of inulin and p-aminohippuric acid was assessed by gastrin radioimmunoassay. In 23 fasting patients there was no significant difference in arterial gastrin (37.7 pg/ml serum +/- 25.1 S.D.) and the renal vein gastrin (35.9 +/- 24.6), resulting in a renal extraction ratio for gastrin not significantly different from zero (p greater than 0.5). The results in three patients indicated no extraction of gastrin for two consecutive periods after a protein-rich meal.