Prostaglandins and the release of LHRH from hypothalamic synaptosomes. Effects of indomethacin pretreatment.
The possible role of prostaglandins (PGs) in the hypothalamic control of ovulation has been investigated by studying the effects of indomethacin (ID) and PGs on the release of luteinizing hormone-releasing hormone (LHRH) from hypothalamic synaptosomes. Female rats were chronically pretreated with ID on diestrus 2 (D2) and proestrus (P), or on diestrus 1 (D1) and D2. Basal LHRH release from hypothalamic synaptosomes prepared from rats pretreated on D2/P was reduced to 48% after a 20-min incubation period, compared with sham-treated animals. ID pretreatment on D1/D2 caused a similar but less marked reduction in LHRH release (to 66% of controls at 20 min). Extraction of the LHRH remaining within the synaptosomal pellet showed that ID pretreatment also reduced the synaptosome content of LHRH. (15S)-15-methyl PGE2 (15-E2) (10(-4) and 10(-6) M) added to the incubating medium stimulated the release of LHRH BY APPROXIMATELY 40%, but this effect was only observed in synaptosomes prepared from ID-treated rats. PGE2 (10(-4) and 10(-6) M) had no significant effect in either sham-treated or ID-treated groups.
D000818:Animals; D004031:Diestrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D007213:Indomethacin / Q000008:administration & dosage* / Q000494:pharmacology; D011247:Pregnancy; D011359:Proestrus; D011458:Prostaglandins E / Q000008:administration & dosage* / Q000494:pharmacology; D011459:Prostaglandins E, Synthetic / Q000008:administration & dosage; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D011458:Prostaglandins E; D011459:Prostaglandins E, Synthetic; D007987:Gonadotropin-Releasing Hormone; D007213:Indomethacin