Properties of somatostatin-like immunoreactive polypeptides in the canine extrahypothalamic brain and stomach

E. S. Zyznar, J. M. Conlon, V. Schusdziarra, Roger H Unger

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

Polypeptides with somatostatin-like immunoreactivity (SLI) and approximate molecular weights of 12, 000, 3, 000, and 1, 600 were isolated from acid extracts of the canine extrahypothalamic brain and stomach by affinity chromatography, ion exchange, gel filtration, and isoelectric focusing. The 12, 000-dalton SLI was acidic, whereas the 3, 000- and 1, 600-dalton forms were basic molecules. All SLI fractions diluted proportionally in a RIA employing an antibody directed toward the central region of somatostatin. Like synthetic somatostatin, the 1, 600- dalton SLI inhibited pentagastrin-stimulated gastric acid secretion in rats. Neither of the two larger forms of SLI were dissociated by 6 M guanidinium HC1. However, treatment with dithiothreitol, which reduces disulfide bonds, resulted in the conversion of a large portion of the 12, 000-dalton SLI to the 1, 600- dalton form. These data are compatible with a model of a 12, 000- dalton SLI consisting of somatostatin bound to an acidic polypeptide by a peptide bond and a isulfide bond. Variations in the relative rates of hydrolysis of the peptide bonds and reductionof the disulfide bonds in different tissues may result in three forms of the 12, 000-dalton polypeptide in which both bonds are intact or one of the two bonds is cleaved.

Original languageEnglish (US)
Pages (from-to)1426-1431
Number of pages6
JournalEndocrinology
Volume105
Issue number6
DOIs
StatePublished - Dec 1979

ASJC Scopus subject areas

  • Endocrinology

Fingerprint Dive into the research topics of 'Properties of somatostatin-like immunoreactive polypeptides in the canine extrahypothalamic brain and stomach'. Together they form a unique fingerprint.

  • Cite this