title: Metabolism of arachidonic acid in vitro by ovine conceptuses recovered during early pregnancy.
abstract: Metabolism of [3H] arachidonic acid ([3H] AA) and synthesis of prostaglandins were examined with ovine conceptuses and endometrial slices collected on various days after mating. Tissues were incubated for 24 hr with or without 5 microCi of [3H] AA and with 200 micrograms radioinert AA. In experiment 1, results of chromatography indicated that conceptuses collected on days 14 and 16 after mating metabolized [3H] AA to PGE2, PGF2 alpha, PGFM, 6-keto-PGF1 alpha, and to unidentified compounds in three chromatographic regions. One of these regions (region I) contained triglycerides. Endometrial slices metabolized only small amounts of the [3H] AA to prostaglandins. In experiment 2, results of radioimmunoassays indicated that day 14 conceptuses released somewhat similar amounts (ng/mg tissue) of PGF2 alpha (32.1 +/- 17.9), PGFM (8.4 +/- 6.2), PGE2 (12.3 +/- 7.5) and 6-keto-PGF1 alpha (41.4 +/- 4.8), whereas day 16 conceptuses released more (P less than .05) PGF2 alpha (9.0 +/- 4.1) and 6-keto-PGF1 alpha (15.9 +/- 2.7) than PGE2 (0.9 +/- 0.2) or PGFM (0.5 +/- 0.08). Day 14 and 16 endometrial slices released (ng/mg tissue) more (P less than .05) PGFM (3.0 +/- 0.2) and 6-keto-PGF1 alpha (4.0 +/- 0.4) than PGF2 alpha (0.5 +/- 0.08) or PGE2 (0.05 +/- 0.02). In experiment 3, conceptuses were recovered on days 16, 20 and 24 of pregnancy and incubated with [3H] AA to determine the effects of indomethacin on [3H] AA metabolism. In general, indomethacin (Id; 4 X 10(-4) M) reduced (P less than .05) the percentage of total dpm recovered as prostaglandins, but Id increased the release of chromatographic region I. Experiment 4 was conducted with day 16, 20 and 24 conceptuses to evaluate the time course of metabolism of [3H] AA, and the appearance of region I and of prostaglandins. In general, the percentage of total dpm in region I increased as the percentage of dpm as [3H] AA decreased. The percentage of dpm as prostaglandins increased as the percentage of dpm in region I decreased. Prostaglandins, probably essential for embryonal survival and development, were synthesized in vitro by ovine conceptuses.
mesh_terms: D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D001755:Blastocyst / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D011247:Pregnancy; D011453:Prostaglandins / Q000096:biosynthesis*; D012756:Sheep
chemical_list: D001095:Arachidonic Acids; D011453:Prostaglandins; D016718:Arachidonic Acid; D007213:Indomethacin