Somatostatin inhibits growth hormone-releasing factor-stimulated adenylate cyclase activity in GH, cells.
GH3 cells were used to study the effect of rat growth hormone-releasing factor on adenylate cyclase activity and its interaction with somatostatin. Rat GRF stimulates adenylate cyclase activity (ED5 0 = 6 X 10(-8) M) and somatostatin-14 inhibits this GRF-stimulated activity in a non-competitive manner without affecting the basal enzyme levels. Inhibition by somatostatin-14 is observed at concentrations as low as 10(-11) M and the half-maximal effect is obtained with 10(-8) M. Somatostatin-28 is more potent than SS-14 and has an ED5 0 of 3 X 10(-11) M. VIP is more active than rat GRF in stimulating adenylate cyclase activation. We conclude that in GH3 cells rat GRF behaves as a partial VIP agonist by interacting with VIP-preferring receptors and its effects are inhibited by somatostatin.
Reyl-Desmars
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Zeytin
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D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D010911:Pituitary Neoplasms / Q000201:enzymology*; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects; D018005:Receptors, Vasoactive Intestinal Peptide; D013004:Somatostatin / Q000494:pharmacology*; D053561:Somatostatin-28; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D000067956:Adenylyl Cyclase Inhibitors; D011956:Receptors, Cell Surface; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D053561:Somatostatin-28; D013007:Growth Hormone-Releasing Hormone; D000262:Adenylyl Cyclases