Serum gastrin concentration in chronic renal failure.

On the basis of the existing experimental and clinical studies about the factors affecting the appearance of hypergastrinemia in renal failure, it can be concluded that the kidney plays an important, but not the only, role in the degradation of endogenous gastrin in humans. In this process the key role is played by the blood flow through the kidney, the preservation of the peritubular capillary system, and the functional kidney mass. Glomerular filtration has no particular importance in the extraction of gastrin from the circulation, while through the urine only a small amount of gastrin is excreted. In the decomposition of a part or at least some molecular gastrin forms, an important role is played by the capillary systems of extra-renal tissue. One further conclusion is that hypergastrinemia in patients with renal failure is the result of the combined effects of the reduced catabolism of gastrin in the kidney and its increased synthesis which is for the most part connected with hypochlohydria and secondary hyperparathyroidism. In patients with renal failure there exists the inhibition of the gastrin acid secretion which is the cause of the weakening of the mechanism of the feedback connection between HCl and gastrin, while because of a permanent stimulation of G-cells, the hyperplasia of these cells develops, as well as the increased secretory activity, and hypergastrinemia. Parietal cells become less sensitive to a permanently increased serum gastrin concentration but still capable of reacting to the maximal stimulus. In patients with renal failure, especially those with extreme hypergastrinemia, there develops the increased concentration of large, mainly biologically inactive (big big gastrin, component I) molecular forms of gastrin.