Effects of the novel GH secretogogue, hexarelin on GH secretion and phosphatidylinositol hydrolysis by human pituitary somatotrophinomas in cell culture.
The effects of the novel GH-releasing hexapeptide, Hexarelin, on cultured human pituitary somatotrophinomas were investigated. Hexarelin (0.01-100 nmol/L) dose-dependently stimulated GH secretion up to 4.6-fold. Maximal effects occurred with 10 nmol/L. These effects were very similar to those observed with GHRP-6. The effects of Hexarelin were reduced by phloretin, an inhibitor of protein kinase C (PKC). The rate of phosphatidylinositol (PI) hydrolysis was markedly increased by Hexarelin in a dose-dependent manner. These results demonstrated that Hexarelin could directly stimulate GH secretion by human pituitary somatotrophs in a PKC-dependent manner, probably via activation of the PI transduction system.
Liu
Q
Q
Department of Pediatrics, Xiehe Hospital, Tongji Medical University, Wuhan 430022.
Lei
T
T
Liu
K
K
Bai
X
X
Adams
E
E
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D009842:Oligopeptides / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
D009842:Oligopeptides; D010716:Phosphatidylinositols; C086184:hexarelin; D013006:Growth Hormone