Further Studies on the Rôle of the Uterus in the Regulation of Corpus Luteum Function in Sheep

It has been well established that removal of the uterus in many mammalian species results in the prolongation of the function and life-span of corpora lutea (Bland & Donovan, 1966; Anderson, Bland & Melampy, 1969; Caldwell, Rowson, Moor & Hay, 1969; Schomberg, 1969; Caldwell, 1970). Furthermore, most evidence suggests that uterine transplantation to ectopic sites can at least partially reverse the extended life-span of the corpora lutea in hysterectomized animals (see Caldwell, 1970, for review). When these studies were extended to test various extracts of uterine tissue or flushings, however, the results were not conclusive. Both success and failure have been reported in the attempt to influence corpus luteum function in hysterectomized animals using extracts of uterine origin given by several routes of administration in various test animals and bioassay systems (Schomberg, 1969; Caldwell, 1970). Previous work has also