mRNA expression of prolactin receptor in sheep pituitary and its effect on maternal behavior.

Prolactin receptor (PRLR) is the specific receptor for prolactin. Brain-specific control of PRLR gene expression is correlated with the induction of maternal behavior. The aim of this study was to investigate the dynamic changes in the PRLR mRNA level in the sheep pituitary gland and its effect on ewe maternal behavior. The mRNA expression of PRLR during non-pregnancy stage was maintained at low but detectable levels, as was the case during mid-gestation. After that, expression began increasing and reached a maximum during the early postpartum followed by a gradual decline during the mid-postpartum and late postpartum stages. A trend of higher PRLR mRNA expression was observed during the postpartum stage relative to the non-pregnancy and pregnancy stages. Expression of PRLR mRNA was significantly higher in the normal maternal behavior group than that in the abnormal maternal behavior group. There may be a correlation between PRLR mRNA expression and ewe maternal behavior, especially in early postpartum.