Sex steroids modulate NADPH-diaphorase expression in the postnatal adrenal neurons of the rat

The rat adrenal gland contains nitric oxide-producing ganglion cells, contributing to its innervation. In a previous study postnatal number and morphology of these adrenal neurons were analyzed by NADPH-diaphorase histochemistry in the two sexes. A transient sex-related difference in the number of NADPH-diaphorase positive neurons per adrenal gland was found at postnatal day 10, when the number of stained neurons in males was nearly twice that found in females. In the present work we studied the effects of perinatal hormonal manipulation on the number of adrenal NADPH-diaphorase-positive neurons during the second postnatal week. The number of labeled adrenal neurons at postnatal day 10 was higher in females receiving perinatal androgen treatment than in control untreated females, and was similar to that of control untreated males. In contrast, in males that underwent perinatal deprivation of testosterone the number of labeled adrenal neurons was lower than in control males, and similar to that of control females. These differences were found in both the adrenal cortex and medulla. In males and in testosterone-treated females there was a higher proportion of stained multipolar neurons than in females and in androgen-deprived males. No intergroup differences were found in the size of stained neurons. Thus, we demonstrated that the postnatal difference in the number of NADPH-diaphorase-positive adrenal neurons in the two sexes is related to the epigenetic action of gonadal hormones during perinatal maturation.