Sites of paradoxical action of the LHRH agonist (D-Trp6)-LHRH.
Immature intact and hypophysectomized female rats, which were primed with gonadotropin, were injected subcutaneously with 0.9% saline or 0.2 or 2 microgram of (D-Trp6)-LHRH once daily for 7 days. Ovarian LH/hCG receptors and ovarian weight were measured 24 hours after the last analog or saline injection. A significant reduction (P < 0.01) of ovarian LH/hCG receptors in both intact and hypophysectomized rats was observed following administration of (D-Trp6)-LHRH in doses as low as 0.2 microgram/day. A significant decrease was observed in the ovarian weight of 2 microgram-treated rats (P < 0.05). The dramatic loss of ovarian LH/hCG receptors in hypophysectomized rats induced by (D-Trp6)-LHRH may indicate that the analog has a direct effect on the ovaries.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007016:Hypophysectomy; D009929:Organ Size / Q000187:drug effects; D010053:Ovary / Q000033:anatomy & histology / Q000187:drug effects*; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011974:Receptors, LH; D017329:Triptorelin Pamoate
D011956:Receptors, Cell Surface; D011974:Receptors, LH; D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone