Increased production of ovarian thromboxane in gonadotropin-treated immature rats: relationship to the ovulatory process.
Thromboxane (TX) B2, a stable metabolic product of hydrolysis of TXA2, was measured by radioimmunoassay in tissue extracts of ovaries of immature rats pretreated with pregnant mare's serum gonadotropin and human chorionic gonadotropin. Ovarian concentrations of TXB2 increased before, and remained elevated after, the time of ovulation. In a subsequent study, ovulation was inhibited in a dose-dependent fashion by a reported TXA2 receptor antagonist, AH23848. Nevertheless, inhibition of the preovulatory rise in synthesis of TXB2 by furegrelate (a thromboxane synthetase inhibitor) did not prevent ovulation. Nor was the blockade of ovulation caused by indomethacin (a cyclooxygenase inhibitor) reversed by a TXA2 mimetic (U-46619). It does not appear that a preovulatory increase in ovarian thromboxane is an obligatory component of the ovulatory mechanism of gonadotropin-primed immature rats.
Wilken
C
C
Department of Animal Science, University of Wyoming, Laramie 82071.
Van Kirk
E A
EA
Slaughter
R G
RG
Ji
T H
TH
Murdoch
W J
WJ
D000818:Animals; D001572:Benzofurans / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D006062:Gonadotropins / Q000494:pharmacology*; D006064:Gonadotropins, Equine / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D010053:Ovary / Q000187:drug effects* / Q000378:metabolism; D010060:Ovulation / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013929:Thromboxane B2 / Q000096:biosynthesis*; D013931:Thromboxanes / Q000037:antagonists & inhibitors
D001572:Benzofurans; D001713:Biphenyl Compounds; D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D006064:Gonadotropins, Equine; D013931:Thromboxanes; D013929:Thromboxane B2; C046926:AH 23848; C039936:furegrelate; D007213:Indomethacin