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Somatostatin structure-activity studies in the stomach.
B H Hirst1, L M Botana, E Arilla
1Department of Physiological Sciences, University of Newcastle upon Tyne, Medical School, UK.
Hormone Research
|January 1, 1988
Summary
Somatostatin derivatives were tested for their ability to inhibit gastric functions in cats. Somatostatin-14 showed greater potency than somatostatin-28, with varying effects observed among different analogues.
Area of Science:
- Gastroenterology
- Endocrinology
- Pharmacology
Background:
- Somatostatin is known to inhibit gastric exocrine functions.
- Its mechanism may be independent of gastrin secretion blockade.
Purpose of the Study:
- To investigate the suppressive effect of somatostatin derivatives on gastric exocrine functions.
- To compare the potency of different somatostatin analogues in a feline model.
Main Methods:
- Cats with cannulated gastric fistulas were used.
- Pentagastrin stimulation was applied.
- Various somatostatin derivatives were administered and their effects on gastric function and hormone release were analyzed.
Main Results:
- Somatostatin-14 was more potent than somatostatin-28 in inhibiting gastric function in this model.
- Substituted analogues showed variable effects; one cyclic pentapeptide lacked gastric inhibitory properties, while a related peptide with a benzyl-protecting group on Thr was only devoid of gastric effect.
- The octapeptide SMS 201-995, potent in rats and humans, did not maximally suppress acid output in cats.
Conclusions:
- Differences in the gastric effects of somatostatin derivatives may be due to selective binding to specific receptor subsets in the stomach mucosa.
- Further studies with short cyclic somatostatin analogues are needed to clarify the relationship between peptide structure and gastric secretion inhibition.