17-beta-estradiol potentiates luteinizing hormone glycosylation and release induced by veratridine, diacylglycerol, and phospholipase C in rat anterior pituitary cells.
We determined the effect of 17 beta-estradiol (E2) on synthesis and release of luteinizing hormone (LH) induced by drugs which activate intracellular signal transduction mechanisms in rat anterior pituitary cells. Cells were pretreated with E2 (6 x 10(-10) M) or diluent for 24 h, then washed and incubated for 4 h with E2 or diluent, respectively, in the presence or absence of drugs. LH translation and glycosylation were monitored by measuring incorporation of [14C]alanine and [3H]glucosamine, respectively, into total (medium plus cells) immunoprecipitable LH. Immunoreactive LH (IRLH) was measured by radioimmunoassay. Gonadotropin-releasing hormone (GnRH, 1 nM), veratridine (5 microM), L-alpha-1,2-dioctanoyl glycerol (C8, 200 microM), and phospholipase C (PLC, 0.24 U/ml) all increased (p less than 0.01) medium IRLH, [3H]glucosamine-LH, and [14C]alanine-LH, and total [3H]glucosamine-LH in both E2- and diluent-treated cells. Total IRLH or [14C]alanine-LH were not increased by any treatment. E2 alone slightly increased (p less than 0.05) basal medium IRLH and [3H]glucosamine-LH. The stimulatory effects of E2 on basal medium [14C]alanine-LH and total [3H]glucosamine-LH were inconsistent. E2 potentiated (p less than 0.01) the effects of veratridine, C8, PLC, and GnRH on medium IRLH, and medium and total [3H]glucosamine-LH. E2 also potentiated (p less than 0.01) the effects of veratridine, PLC, and GnRH, but not of C8, on medium [14C]alanine-LH. In contrast, E2 did not increase either precursor uptake or incorporation of precursor into total protein in the presence of any secretagogue.(ABSTRACT TRUNCATED AT 250 WORDS)
Liu
T C
TC
Department of Veterinary Biosciences, University of Illinois, Urbana.
Jackson
G L
GL
D000409:Alanine / Q000378:metabolism; D000818:Animals; D004075:Diglycerides / Q000494:pharmacology*; D004357:Drug Synergism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005944:Glucosamine / Q000378:metabolism; D005989:Glycerides / Q000494:pharmacology*; D006031:Glycosylation; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D015398:Signal Transduction / Q000187:drug effects; D010738:Type C Phospholipases / Q000494:pharmacology*; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
D004075:Diglycerides; D005989:Glycerides; C044295:1,2-dioctanoylglycerol; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D014701:Veratridine; D007986:Luteinizing Hormone; D010738:Type C Phospholipases; D014702:Veratrine; D005944:Glucosamine; D000409:Alanine