Effects of recombinant ovine interferon tau, placental lactogen, and growth hormone on the ovine uterus

Studies were conducted to determine effects of intrauterine administration of recombinant ovine interferon tau (IFN tau), placental lactogen (PL), and growth hormone (CH) on endometrial function. In the first study, administr ation of IFN tau to cyclic ewes for one period (Days 11-15) resulted in an interestrous interval (IEI) of -30 days, whereas administration for two per iods (Days 11-15 and Days 21-25) extended the IEI to greater than 50 days. Administration of IFN tau from Days 11 to 15 and of PL or CH from Days 21 t o 25 failed to extend the IEI more than for IFN tau alone, In the second st udy, effects of IFN tau, FL, and GH on endometrial differentiation and func tion were determined in ovariectomized ewes receiving ovarian steroid repla cement therapy. Endometrial expression of mRNAs for estrogen receptor (ER), progesterone receptor (PR), and oxytocin receptor (OTR) were not affected by PL or GH treatment; however, uterine milk protein mRNA levels and stratu m spongiosum gland density were increased by both PL and GH treatments. Col lectively, results indicated that 1) PL and GH do not regulate endometrial PR, ER, and OTR expression or affect corpus luteum life span; 2) down-regul ation of epithelial PR expression is requisite for progesterone induction o f secretory gene expression in uterine glandular epithelium; 3) effects of Pt and GH on endometrial function require IFN tau; and 4) Pt and GH regulat e endometrial gland proliferation and perhaps differentiated function.