ADRENOCORTICAL AND GONADAL EXPRESSION OF THE MAMMALIAN FTZ-F1 GENE ENCODING AD4BP SF-1 IS INDEPENDENT OF PITUITARY CONTROL/

Ad4BP/SF-1 is a transcription factor essential for the development of the adrenal gland and the gonads as well as for the maintenance of the ir functions through regulating tissue-specific gene transcription. In the whole body, hypothalamo-pituitary-gonadal and -adrenal axes are k nown to play prominent roles in mediating the function of the gonads a nd adrenal, In this study, the effects of the tropic peptide hormones secreted by the pituitary on the regulation of the rat Ftz-F1 (rFtz-F1 ) gene encoding Ad4BP/SF-1 were investigated, Immunochemical studies r evealed that Ad4BP/SF-1 was expressed even in the adrenal cortex of hy pophysectomized rats, Such persistent expression of Ad4BP/SF-1 was als o observed in the testes and ovaries of the hypophysectomized animals. In contrast to Ad4BP/F-1, the expressions of steroidogenic P450s were reduced significantly. The transcriptional activities of the endogeno us and transfected rFtz-F1 genes were examined with Y-1 and I-10 cells derived from mouse adrenocortical and testicular Leydig cell tumors, respectively, Neither gene appeared to be activated significantly by c AMP, whereas both endogenous and exogenous CYP11A genes encoding P450( SCC) were activated. Taken together, these observations indicate that the expression of the rFtz-F1 gene is mainly regulated by a mechanism independent of the neuroendocrine axes.