Prostaglandin production by ovine embryos and endometrium in vitro

For Day-14 sheep embryos, mean (+/- s.e.m., n = 7) PGE release was 20.2 +/- 5.0, 13.0 +/- 1.9 and 6.7 +/- 1.9 ng . mg tissue-1 . h-1 after 0.5, 4.5 and 8.5 h of culture respectively, while mean PGF release rates (+/- s.e.m.) for the same periods were 98.5 +/- 24.4, 49.3 +/- 16.3 and 16.5 +/- 5.4 ng . mg tissue-1 . h-1, respectively. Total quantities of PGE and PGF released after 8.5 h of culture were 707 ng and 1833 ng per embryo, respectively. Embryos (n = 21) collected between Days 13 and 15 of gestation contained 25.4 +/- 6.9 ng PGE and 66.2 +/- 23.2 ng PGF/embryo. A total PG release 28 times the embryonic content of PG suggested active PG production by the embryos. Co-culture of embryos with endometrium resulted in PG release rates which were not significantly higher than those from embryos cultured alone. Release of PGE and PGF from embryos declined with time, that for PGF being significantly (P less than 0.05) reduced after 8.5 h incubation. Co-culture of embryos and endometrium had no effect of rate of decline of PG production over time. Day 14 endometrium from pregnant or non-pregnant ewes produced very small quantities of both PGs by comparison with embryos, and there was no consistent trend for PG production rate over time.