Oestrogen receptors and protein synthesis in caruncular and intercarun- cular endometrium of sheep before implantation

Abstract

The rate of protein synthesis was higher in caruncular (P<0.05) and intercaruncular endometrium (P<0.01) of pregnant compared to non-pregnant ewes on Day 11 (Day 0 = day of oestrus), but not on Days 9, 13 and 15. Cytosolic oestrogen receptor concentrations (nmol/mg protein) were lower in caruncular endometrium of pregnant ewes than in non-pregnant ewes on Days 9 (P<0.02), 13 (P<0.05) and 15 (P<0.001) but not on Day 11. In intercaruncular endometrium, the receptor values were lower on Day 15 (P<0.02) of pregnancy compared to non-pregnancy, but not on the other days. The dissociation constant (0.75-2.55 x 10-10 M) of oestradiol-17β for cytosolic receptors was similar in both tissues, regardles..