EFFECTS OF INTERFERON-TAU AND PROGESTERONE ON OESTROGEN-STIMULATED EXPRESSION OF RECEPTORS FOR OESTROGEN, PROGESTERONE AND OXYTOCIN IN THE ENDOMETRIUM OF OVARIECTOMIZED EWES

摘要

The effects of recombinant ovine interferon-tau (IFN-tau) and progesterone on oestrogen-stimulated expression of endometrial receptors for oestrogen (ER), progesterone (PR) and oxytocin (OTR) were determined in ovariectomized ewes, Cyclic ewes (n = 16) were ovariectomized and fitted with uterine catheters on Day 4 of the oestrous cycle (Day 0, oestrous) and assigned randomly in a 2x2-factorial arrangement to receive daily intrauterine injections of either recombinant ovine IFN-tau (roIFN-tau; 2x10(7) anti-viral units) or control proteins from Day 11 to Day 15 and 50 mg progesterone from either Day 4 to Day 10 (E-P) or Day 4 to Day 15 (E+P). All ewes received 50 mu g oestradiol-17 beta on Days 13, 14 and 15 and were hysterectomized on Day 16, In control ewes, endometrial ER mRNA, PR protein and OTR density were greater in E-P- than E+P-treated ewes. In E-P ewes, roIFN-tau decreased oestrogen-stimulated increases in ER and OTR, but not PR expression compared with control ewes, In E+P ewes, endometrial ER mRNA and protein, PR mRNA and protein, and OTR levels were lower in roIFN-tau-treated ewes than control ewes. Immunoreactive ER and PR were absent in the endometrial luminal and superficial glandular epithelium of roIFN-tau compared with control ewes, but were present in the deep glandular epithelium and stroma regardless of steroid or protein treatment. These results indicate that progesterone affects oestrogen-induced increases in endometrial ER, PR and OTR expression in the PR(+) deep glandular epithelium and stroma, whereas IFN-tau suppresses oestrogen-induced increases ER, PR and OTR expression in the PR(-) luminal and superficial glandular epithelium. These combined actions of IFN-tau and progesterone to suppress oestrogen-induced increases in endometrial OTR formation would prevent pulsatile production of luteolytic prostaglandin F-2 alpha by the endometrium during early pregnancy.