Prolactin (PRL) promotes maternal behavior (MB), a complex pattern of behavior aimed at maximizing offspring survival. 3alpha,5alpha-reduced neurosteroids may also regulate MB. Indeed, PRL, 3alpha,5alpha-reduced neurosteroids, and 5alpha-reductase (5alpha-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 5alpha-R. In the present study we quantified mRNA levels of both 5alpha-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 5alpha-R isozymes were significantly increased in male and female rats by sulpiride, directly or via sulpiride-induced hyperprolactinemia. Since 3alpha,5alpha-reduced neurosteroids and PRL exert anxiolytic effects in response to stress, these molecules and 5alpha-R may possibly participate in a common pathway of significant adaptation to stress situations.

SummaryProlactin (PRL) is implicated in prostate growth and in the development and regulation of benign prostatic hypertrophy (BPH) and prostate cancer (PCa). PRL may exert its effects on prostate in synergism with androgens. The most active androgen in the prostate is the 5a-dihydrotestosterone (DHT) obtained from testosterone by the 5a-reductase (5a-R) enzyme, which is expressed in the prostate as two isozymes, 5a-R1 and 5a-R2. In this study, sulpiride, a prolactin-secretion inductor, was administered to male rats. mRNA levels of 5a-R1 and 5a-R2 were measured in prostate of controls and sulpiride-treated rats, using one-step quantitative RT-PCR coupled with laserinduced fluorescence capillary electrophoresis (LIF-CE). Results demonstrated that sulpiride-induced hyperprolactinemia is associated with an increase in mRNA levels of both 5a-R1 and 5a-R2 in prostate of adult rats. Although a direct effect of sulpiride on prostate gland cannot be ruled out, hyperprolactinemia may be a factor to be considered in aging males, in whom prostatic diseases such as BPH and PCa are more frequent. IUBMBIUBMB Life, 60(1): [68][69][70][71][72] 2008

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