Rate of disappearance of circulating endogenous gastrin in dogs.

In five awake mongrel dogs, endogenous gastrin was released by continuous irrigation of the antrum with acetylcholine. After 60 minutes of antral perfusion, the entire vascular supply of the antrum was suddenly and totally occluded, and serial samples of peripheral blood were taken for measurement of gastrin. The rate of disappearance of endogenous gastrin was caluclated by standard linear regression analysis; the calculated half-life of endogenous gastrin was 8.62 minutes. Analysis of the data suggests that the disappearance rate of endogenous gastrin could be explained by two distinct half-lives: one of 2.8 minutes (which is similar to the half-time in dogs of both 14- and 17 -amino acid gastrin), and another of 15.4 minutes (which is similar to the half-time of 34 -amino acid gastrin). Physiologically released gastrin is a mixture of three or more molecular forms of gastrin and the half-life of 8.62 minutes probably represents the disappearance half-time of this mixture.