Removal of IR-GIP by the kidneys in man, and the effect of acute nephrectomy on plasma GIP in rats.

In a group of 10 patients undergoing routine cardiac catheterization, mean plasma gastric inhibitory polypeptide (GIP) was significantly lower (p = 0.002) in blood drawn from the renal vein than in blood drawn from the hepatic vein, the right atrium, the femoral vein, and the femoral artery, demonstrating the removal of immunoreactive GIP by the kidneys. In a group of eight nephrectomized rats, mean plasma GIP was significantly higher 30 and 60 min after start of intraduodenal glucose infusion (p = 0.03 and p = 0.002, respectively) as compared with eight control rats, which probably reflects reduced removal of GIP in the nephrectomized group.