Possible role of prolactin during the oestrous cycle and gestation in the ewe

Abstract

Results show that prolactin has a luteotrophic effect on cycling and pregnant ewes, and is a constituent of the luteotrophic complex, which includes LH. It seems that the normal secretion of prolactin is usually higher than this luteotrophic function requires. Study of the luteotrophic role of anterior pituitary hormones at the end of the first mth of gestation reveals the progressive appearance of placental factors with LH and prolactin. Studies undertaken in vitro tend to demonstrate the important role of prolactin in the establishment of lactogenesis in the ewe during gestation. Further experiments are necessary to define the mode of action of prolactin on the mammary gland and its relation to that of steroid hormones.