The relationship between the chronic intrauterine injection of PGE2 every four hours adjacent or opposite to the corpus luteum on luteal function was studied. Intrauterine infusions every four hours of PGE2 (500 mug) from days 10 to 17 postestrus maintained luteal function only when infused into a uterine horn adjacent to a luteal-bearing ovary of unilaterally ovariectomized sheep with surgically separated uterine cornua. These data are compatible with the hypothesis that PGE2 is a good candidate for the antiluteolysin since it works only through a similar local pathway as the embryo during early pregnancy to sustain the corpus luteum.
Concentrations of progesterone in uterine and arterial tissue and in uterine and jugular venous plasma were determined. Blood was collected on Days 4 and 9 postestrus from the jugular vein and the first and last venous branches draining each uterine cornu; uterine tissue and arteries were subsequently collected. Progesterone was greater (p less than 0.05) in the cranial third than in the middle or caudal thirds of the uterine horn adjacent to the corpus luteum (CL)-bearing ovary or in any third of the contralateral horn. Progesterone in uterine arterial segments adjacent to the CL-bearing ovary was higher (p less than 0.05) than in contralateral segments. Progesterone was higher (p less than 0.05) in blood from the first venous branch of the cranial third of the uterine cornu adjacent to the ovary with the CL, than in the last branch of the caudal third, or contralateral horn, or in jugular blood. When oviductal veins were resected on Day 9 postestrus, progesterone in the first vein draining the cranial third of the uterine cornu adjacent to the CL-containing ovary was not different (p greater than 0.05) 48 h after resection than in the same vessel in the opposite horn or in jugular blood. We concluded that progesterone and other ovarian products may be delivered to the uterus locally.
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