Effects of superovulation, arachidonic acid or endometrium on release of prostaglandins and synthesis of proteins by bovine trophoblast

This study was conducted in vitro to examine factors that may regulate prostaglandin release by bovine trophoblast and endometrial slices. Trophoblastic tissues and endometrial slices were recovered from superovulating and normally-ovulating cattle on day 16 or 20 of pregnancy and incubated for 24 h. Release of PGF2 alpha and 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and incorporation of [14C]-leucine into proteins were quantified and expressed per microgram DNA, which gives a measure of cellular activity. Activity of trophoblastic tissue for synthesizing protein was decreased (P less than .05) and for releasing PGFM was increased (P less than .05) on day 20 compared to day 16 of pregnancy. Neither superovulation nor day of pregnancy altered trophoblastic activity for releasing PGF2 alpha. Superovulation increased (P less than .05) endometrial release of PGF2 alpha. Endometrial release of PGF2 alpha was less (P less than .05) on day 20 than on day 16 of pregnancy. When arachidonic acid (0, 100, 200 or 400 micrograms) was added at the start of incubation, trophoblastic release of PGF2 alpha changed (P less than .05) quadratically with dose of arachidonic acid. When arachidonic acid was added 8 h after the start of incubation, trophoblastic release of PGF2 alpha increased linearly (P less than .01) with dose of arachidonic acid. Adding arachidonic acid to incubation medium did not affect trophoblastic or endometrial protein synthesis. Endometrial slices suppressed (P less than .05) trophoblastic protein synthesis and release of PGF2 alpha. Apparently, endometrium can modulate trophoblastic release of prostaglandins and synthesis of proteins in vitro, and trophoblastic tissue from superovulated cattle 16 or 20 days pregnant can be used to study trophoblastic synthesis of prostaglandins and proteins.