title: [High biological activity of the synthetic counterparts of hypothalamic somatostatin-28 and somatostatin-25].
abstract: We have isolated from extracts of ovine hypothalamus two molecules characterized as somatostatin-28 and somatostatin-4-28 (referred to as somatostatin-25). They were reproduced by synthesis. In equimolar ratios and depending upon the experimental conditions, synthetic somatostatin-28 and somatostatin-25 are 3 to 14 times more potent than somatostatin-14 to inhibit the basal in vitro secretion of growth hormone. These results suggest that somatostatin-14 as originally isolated, is a biologically active fragment of a larger molecule of greater specific activity, rather than somatostatin-28 being a precursor of the tetradecapeptide.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D013006:Growth Hormone / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D011498:Protein Precursors; D051381:Rats; D013004:Somatostatin / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D053561:Somatostatin-28
chemical_list: D011498:Protein Precursors; D013004:Somatostatin; C026568:somatostatin 25; D053561:Somatostatin-28; D013006:Growth Hormone
vernacular_title: Haute activité biologigue des répliques synthétiques de somatostatine-28 et somatostatine-25 hypothalamiques.