Studies on ovarian prostaglandin production in relation to ovulation in the rat.
Prostaglandin (PG) and thromboxane (TX) synthesizing capacities of the rat ovary were measured at 4-h intervals during the 4-day oestrous cycle of the rat. Production of PGE-2, PGF-2 alpha, 6-oxo-PGF-1 alpha and TXB-2 increased 5-fold, 1.6-fold, 1.7-fold and 1.7-fold, respectively, between 18:00 h on the day of pro-oestrus and 02:00 h at oestrus. This preferential stimulation of ovarian PGE-2 production, after the ovulatory surge of LH before ovulation, provides further evidence for the involvement of ovarian PGE-2 in ovulation in the rat. These increases in ovarian PG production were not due to differences in arachidonic acid availability, PG metabolism, or the interconversion of PGE-2 and PGF-2 alpha. In addition, the greater stimulation of PGE-2 synthesis was not due to an increase in PGH-2 to PGE-2 synthetase activity. It is concluded that the ovulatory LH surge late in the afternoon of pro-oestrus in the rat causes an increase in ovarian cyclo-oxygenase (PGH-2 synthetase) activity with the majority of the PGH-2 synthesized being directed into the PGE-2-forming pathway.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D015237:Dinoprost; D015232:Dinoprostone; D004971:Estrus; D005260:Female; D010053:Ovary / Q000378:metabolism*; D010060:Ovulation; D011247:Pregnancy; D011453:Prostaglandins / Q000096:biosynthesis*; D011458:Prostaglandins E / Q000096:biosynthesis; D011460:Prostaglandins F / Q000096:biosynthesis; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013929:Thromboxane B2 / Q000096:biosynthesis
D011453:Prostaglandins; D011458:Prostaglandins E; D011460:Prostaglandins F; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D015237:Dinoprost; D015232:Dinoprostone