Influence of sex steroids on the pituitary and the adrenal glands assessed by comprehensive gene expression analysis (CBX66). unidentified

We investigated the differences in gene expression by comparisons of expression profiles obtained from the pituitary and adrenal glands of male and female rats kept under physiological and experimental conditions including surgical operations and exogenous hormone administration. Comparison between physiological male and female rats revealed gene sets that exhibited sex-dependent differences in a pituitary- or adrenal-gland-specific manner. Castration to deplete intrinsic sex steroids altered the expression patterns of the gene sets. In the pituitary gland, the castrated female patterns resembled the physiological and castrated male ones, whereas in the adrenal gland, the castrated male patterns were similar to the physiological and castrated female ones. Exogenous administration of sex steroids after castration further altered the expression patterns. In the pituitary gland of the castrated female rats, testosterone reconstituted the physiologically female-specific patterns. In the pituitary gland of the castrated male and female rats, although estradiol nearly reorganized the physiological female patterns, it enhanced the physiologically sex-dependent differences. In the adrenal gland of the castrated female rats, testosterone regenerated the physiologically male-specific patterns. These results indicate that sex steroids influence gene expression with sex-dependent differences in a tissue-specific manner. Moreover, they imply that estradiol and testosterone predominantly govern the sex-dependent differences of gene expression in the pituitary and adrenal glands, respectively.