Endocrine events associated with endometrial function and conceptus development in cattle [and sheep; review]
1992
Geisert, R.D. (Oklahoma State Univ., Stillwater (USA). Dept. of Animal Science) | Morgan, G.L. (Oklahoma State Univ., Stillwater (USA). Dept. of Veterinary Medicine and Surgery) | Short, E.C. (Oklahoma State Univ., Stillwater (USA). Dept. of Physiological Sciences) | Zavy, M.T. (US Dept. of Agriculture, El Reno (USA))
Regulation and timing of luteolysis during the bovine oestrous cycle is controlled by the initiation and length of progesterone stimulation. Results have demonstrated that early administration of progesterone shortens the interoestrous interval in the ewe and cow, and removal of progesterone stimulation through a progesterone receptor antagonist delays luteolysis in sheep. Current data suggest that down-regulation of progesterone receptors in the uterine epithelium may initiate events involved in the synthesis and release of prostaglandin F2alpha (PFA) for luteolysis. Progesterone is also involved in the stimulation of the uterine secretions that regulate conceptus growth and the release of the bovine trophoblast protein-1 (bTP-1) necessary for inhibiting endometrial PFA release. Conceptus secretion of bTP-1, a Type 1 trophoblast interferon, increases the concentration of a cellular enzyme within the endometrium. The biological role of this enzyme in the establishment of pregnancy is discussed.
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