IS THE INHIBITORY EFFECT OF PROGESTERONE ON ENDOMETRIAL PROSTAGLANDIN-F2-ALPHA PRODUCTION DUE TO AN INHIBITION OF PROTEIN-SYNTHESIS

Progesterone and a high concentration of oestradiol (i) reduced the outputs of prostaglandin (PG) F2α and, to a lesser extent, PGE2 from Day-7 and Day-15 guinea-pig endometrium in culture, but had little or no effect on the output of 6-keto-PGF1α, (ii) prevented the increase in PGH synthase concentrations which normally occur in Day-7 and Day-15 guinea-pig endometrium during culture, and (iii) reduced the synthesis of secreted proteins by Day-15 guinea-pig endometrium in culture. These findings suggest that the inhibitory effect of progesterone and of high concentrations of oestradiol on endometrium PGF2α synthesis is due to an inhibition of the syntheses of proteins involved in PGF2α production. © 1990.