AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 2 97-102, Copyright © 1982 by American Physiological Society
Somatostatin-14 and -28: clearance and potency on gastric function in dogs
A. Seal, T. Yamada, H. Debas, J. Hollinshead, B. Osadchey, G. Aponte and J. Walsh
To examine the significance of somatostatin-14 (S-14) and somatostatin-28
(S-28) in gastric physiology, we compared their relative potencies on acid
secretion in the dog. On a molar infusion basis, S-14 and S-28 appeared to
be equipotent, causing 50% inhibition of peptone meal-stimulated acid
secretion at a dose of 400 pmol . kg-1 . h-1. However, comparison of the
plasma half lives (t 1/2) of the two peptides revealed that S-28
disappeared at a much slower rate (t 1/2 = 2.84 +/- 0.15 min, mean +/- SE,
n = 7) than S-14 (t 1/2 = 0.57 +/- 0.06 min). When acid-inhibitory effect
was compared against increment in plasma concentrations produced by peptide
infusion, S-14 was roughly 10-fold more potent than S-28. No alteration of
gastrin response to peptone was observed at a dose of S-14 or S-28 that
completely abolished acid secretion, suggesting that regulation of acid
secretion is not mediated by gastrin inhibition. Thus, S-14 is a potent and
possibly important physiological inhibitor of gastric acid secretion.
Although circulating S-28 may have importance in regulation of some
biological functions, it appears to play a less prominent role in
regulation of gastric secretion.
