Effects of Sulpiride on Prolactin and mRNA Levels of Steroid 5α-reductase Isozymes in Adult Rat Brain

摘要

Prolactin (PRL) promotes maternal behavior (MB), a complex pattern of behavior aimed at maximizing offspring survival. 3α,5α-reduced neurosteroids may also regulate MB. Indeed, PRL, 3α,5α-reduced neurosteroids, and 5α-reductase (5α-R), the key enzyme in the biosynthesis of these neuroactive steroids, are all increased in stress situations These facts led us to hypothesize a possible interrelation between PRL levels and 5α-R. In the present study we quantified mRNA levels of both 5α-R isozymes in prefrontal cortex of male and female rats after administration of sulpiride, an inductor of PRL secretion. Our results demonstrated that mRNA levels of both 5α-R isozymes were significantly increased in male and female rats by sulpiride, directly or via sulpiride-induced hyperprolactinemia. Since 3α,5α-reduced neurosteroids and PRL exert anxiolytic effects in response to stress, these molecules and 5α-R may possibly participate in a common pathway of significant adaptation to stress situations.