PT  - JOURNAL ARTICLE
AU  - JAN MARIAN
AU  - P. MICHAEL CONN
TI  - Gonadotropin Releasing Hormone Stimulation of Cultured Pituitary Cells Requires Calcium
DP  - 1979 Jul 01
TA  - Molecular Pharmacology
PG  - 196--201
VI  - 16
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/16/1/196.short
4100  - http://molpharm.aspetjournals.org/content/16/1/196.full
SO  - Mol Pharmacol1979 Jul 01; 16
AB  - The requirement for Ca2+ during luteinizing hormone (LH) release stimulated by gonadotropin-releasing hormone (GnRH) was studied in dispersed cultured rat pituicytes. With maximal GnRH stimulation, LH release required 1 mM Ca2+ for optimal stimulation, although basal production was not calcium dependent. Stimulated release was inhibited when cells were incubated in media lacking Ca2+, and by LaCl3 (a potent inhibitor of Ca2+ action) which inhibited GnRH-induced LH release in the presence of Ca2+. The requirement for Ca2+ is specific, since Mg2+ is not as effective, even at elevated concentrations. Two agents that block Ca2+ movement into and within cells, Ruthenium Red and D-600 (methoxy-verapamil), also blocked the release of LH from stimulated pituicytes. The present results demonstrate a specific dependence on calcium for GnRH stimulation of LH release from cultured gonadotrophs. Our observations satisfy some of the criteria require for a postulated role of Ca2+ in stimulus-secretion coupling in this system.