Study on the mechanism and effects of Gly-Tyr-NH2 and Gly-Tyr-Lys on rat luteal cells in vitro.
The action of Gly-Tyr-NH2, (GY-NH2) and Gly-Tyr-LYS(GYK) on 125I-LH binding, cAMP accumulation and progesterone production was investigated. Incubation of rat luteal cells for 2.5 h with GY-NH2 and GYK at dosage of 0.2 mmol/L caused a significant inhibition of basal and gonadotropin-stimulated steroidogenesis. GY-NH2 and GYK were also found to reduce cAMP formation in response to hCG. The activity of adenylate cyclase of luteal cells was inhibited by 0.2 mmol/LGY-NH2 and GYK. GY-NH2 and GYK at a concentration of 0.2 mmol/L were not found to have an inhibitory effect on 8Br-cAMP-stimulated progesterone production. GY-NH2 and GYK did not affect 125I-LH binding to LH receptors on the luteal cell surface. These results suggest that GY-NH2 and GYK inhibit steroidogenesis at the step of gonadotropin-stimulated cAMP formation in luteal cells. Adenylate cyclase in luteal cells was also inhibited.
Wang
N
N
Institute of Materia Medica, CAMS & PUMC, Beijing.
Guan
M
M
Wang
D
D
Lu
G
G
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D000242:Cyclic AMP / Q000096:biosynthesis*; D004151:Dipeptides / Q000494:pharmacology*; D005260:Female; D008184:Luteal Cells / Q000187:drug effects* / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D011374:Progesterone / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
D004151:Dipeptides; D009842:Oligopeptides; C093209:glycyltyrosinamide; D011374:Progesterone; D007986:Luteinizing Hormone; C093210:glycyl-tyrosyl-lysine; D000242:Cyclic AMP; D000262:Adenylyl Cyclases