Influence of renal functional mass on the catabolism of endogenous gastrin in humans.

The influences of renal function and mass on the catabolism of serum gastrin were studied in 27 patients with hypertension caused by unilateral parenchymal renal disease (77.8%), renal artery stenosis (11.1%) and essential hypertension (11.1%). Blood for gastrin analysis was taken by catheterization from the aorta, inferior vena cava, renal veins and cubital vein. Separate renal functions were measured using radioisotope methods and the renal mass was also calculated. Significant differences (p < 0.001) in serum gastrin concentration between the aorta (29.5 +/- 6.7 pmol/l), inferior vena cava (23.4 +/- 5.8 pmol/l) and cubital vein (19.4 +/- 4.5 pmol/l) were found. Extrarenal gastrin extraction amounted to 12.5% and was considerably lower than renal gastrin extraction (20.5%). There was a significant positive correlation between renal gastrin extraction and renal blood flow or renal functional mass. Kidneys have an important, but not exclusive, role in the catabolism of endogenous gastrin in humans. In the catabolism of some, or at least some molecular forms of, gastrin, the capillary systems of extrarenal tissues have an important role.