EXPRESSION OF BASIC FIBROBLAST GROWTH-FACTOR (FGF-2) MESSENGER-RIBONUCLEIC-ACID IS REGULATED BY TESTOSTERONE IN THE RAT ANTERIOR-PITUITARY

Evidence from in vitro studies supports the concept that growth factor s are involved in the function of endocrine organs. We studied the eff ects of target endocrine organs (thyroid, adrenals, and gonads) on lev els of basic fibroblast growth factor (FGF-2) messenger ribonucleic ac id (mRNA) in the anterior pituitary and the hypothalamus of male rats using RNase protection assays. Castration significantly reduced the le vels of FGF-2 mRNA in the anterior pituitary, but not in the hypothala mus. This decrease was restored by testosterone administration. The re gulation of pituitary FGF-2 mRNA involves a specific hormone, i.e. tes tosterone, since neither adrenalectomy nor chemical thyroidectomy affe cts the expression of the gene for FGF-2.