Effects of conceptus and conceptus secretory products on uterine development in the pig

Pregnant gilts (n = 6) were subjected to surgery on Day 3 of pregnancy and uterine horns, within gilts, were assigned to either (1) ligation 15 cm below the uterotubal junction (REST) or (2) ligation proximal to the uterine body (NONREST). On Day 15 of pregnancy gilts were hysterectomized and length and weight of both uterine horns were recorded. NONREST uterine horns were longer (P less than .05) than those of REST, but weights were similar. Conceptuses from the REST uterine horns were retarded in development. Morphometric analysis of surface (SE) and glandular (GE) epithelial cells detected no effect of treatment on height, width, area, nuclear area or percentage of nucleus. Porcine conceptus secretory proteins (pCSP) were obtained from medium in which pig conceptuses, collected on Day 15 of pregnancy, were cultured for 30 h. Culture medium was pooled, dialysed and concentrated by Amicon ultrafiltration for intrauterine infusion. Serum proteins (SP) were obtained from blood collected from a Day 15 pregnant gilt and diluted for intrauterine infusion. Catheters were placed into both uterine horns or cyclic gilts (n = 8) on Day 10 of the oestrous cycle and uterine horns were ligated proximal to the uterine body. Gilts received either oestradiol valerate (E2) (5 mg) or corn oil (CO) on Days 11 and 12. On Days 12-14 each gilt received twice daily infusions of Day 15 pCSP in one uterine horn and SP in the other uterine horn.(ABSTRACT TRUNCATED AT 250 WORDS)