Effect of calcium ion channel antagonists on chorionic gonadotropin secretion.
By using calcium ion channel antagonists such as Verapamil and Nifedipine, we demonstrated that calcium ion channels are involved in human chorionic gonadotropin (hCG) secretion stimulated by gonadotropin releasing hormone (GnRH). Addition of 1 microM Verapamil (Class II inhibitor) resulted in an inhibition of GnRH-stimulated hCG secretion by placenta without affecting basal release. However, while addition of 10 microM Nifedipine (Class I inhibitor) resulted only in partial inhibition, significant inhibition was observed at 100 microM concentration and above. These results suggest that calcium ion channels in placenta appear to be similar although not identical with the channels reported in the pituitary.
Sharma
S C
SC
Department of Biochemistry, Indian Institute of Science, Bangalore.
Rao
A J
AJ
D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002132:Calcium Radioisotopes / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D009543:Nifedipine / Q000494:pharmacology; D010920:Placenta / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D002132:Calcium Radioisotopes; D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D014700:Verapamil; D009543:Nifedipine