Luteinizing hormone but not endothelin can induce a calcium signal in the chicken granulosa cell.
Using the fluorescent calcium-indicator Indo-1 we demonstrated a rapid transient increase of cytosolic calcium level in dispersed chicken granulosa cells in response to 10-100 ng/ml ovine luteinizing hormone (LH). The magnitude of the signal was dose-dependent, it lasted for about 30 seconds and could be provoked even when the extracellular calcium had been chelated by EGTA. A high, 100 ng/ml concentration of LH abolished completely the responsiveness of these cells to a second exposure to the agonist. We conclude, that LH can mobilize calcium ions from internal store(s) via a desenzitizable mechanism. Finally, endothelin--a vasoactive peptide with Ca2(+)-mobilizing activity in glomerulosa cells--was shown to have no effect on the concentration of cytosolic Ca2+ in chicken granulosa cells.
Sahin-Tóth
M
M
Department of Obstetrics and Gynecology, St. Louis University Medical Center, MO 63110-0250.
Tóth
M
M
Hertelendy
F
F
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002645:Chickens; D003600:Cytosol / Q000378:metabolism; D016232:Endothelins / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes; D006107:Granulosa Cells / Q000378:metabolism*; D066298:In Vitro Techniques; D007211:Indoles; D007986:Luteinizing Hormone / Q000502:physiology*
D016232:Endothelins; D005456:Fluorescent Dyes; D007211:Indoles; D007986:Luteinizing Hormone; C048960:indo-1; D002118:Calcium