EFFECTS OF TRANSFORMING GROWTH-FACTOR-BETA-1 ON HUMAN ADRENOCORTICAL FASCICULATA-RETICULARIS CELL DIFFERENTIATED FUNCTIONS

Transforming growth factor-beta 1 (TGF beta 1) has been reported to have a strong inhibitory effect on the specific function of adrenal cells of several species. In the present study, we examined the effects of TGF beta 1 on cultured human fasciculata-reticularis cells. TGF beta 1 alone had no effect on ACTH receptor messenger ribonucleic acid (mRNA) levels and was unable to reduce the strong stimulatory effects of ACTH on its own receptor. However, TGF beta 1 enhanced angiotensin-II type 1 receptor mRNA and binding sites. Treatment with TGP beta 1 increased significantly the levels of 3 beta-hydroxysteroid dehydrogenase mRNA, reduced those of cytochrome P-450 17 alpha-hydroxylase mRNA, and had no effect on cholesterol side-chain cleavage cytochrome P-450 mRNA. Whatever the experimental condition, TGF beta 1 did not reduce basal or ACTH-stimulated cortisol production, but the production of dehydroepiandrosterone sulfate of TGF beta 1-treated cells was always decreased. The effects of TGF beta 1 on 3 beta-hydroxysteroid dehydrogenase mRNA and dehydroepiandrosterone sulfate were opposite the change observed at the time of adrenarche. As adrenal cells express TGF beta 1 mRNA, it is tempting to postulate that a local diminution of TGF beta 1 might be involved in adrenarche. Our findings also illustrate the specific species differences and, therefore, the caution to extrapolate to humans the results observed in other species.