DEMONSTRATION OF THYROTROPHIN β-SUBUNIT MESSENGER RNA IN RAT PITUITARY CELLS IN PRIMARY CULTURE - EVIDENCE FOR REGULATION BY THYROTROPHIN-RELEASING HORMONE AND FORSKOLIN

Abstract

ABSTRACT We have reported previously the effect of thyroid status in vivo on pituitary cytoplasmic concentrations of messenger RNA (mRNA) encoding the thyrotrophin (TSH) β-subunit (Franklyn, Lynam, Docherty et al, 1985). Studies in vitro of the regulation of TSH β gene transcription have been confined to thyrotrophic tumour cells. We now report the demonstration of TSH β-subunit mRNA in non-tumorous rat pituitary cells in primary culture. Treatment of cells with thyrotrophin-releasing hormone (TRH) and with forskolin resulted in a marked increase in cellular concentration of TSH β-mRNA. These results suggest that TRH exerts a direct effect on the pretranslational events involved in TSH synthesis and further that the adenylate cyclase system may be involved in the regulation of synthesis. We have thus described a novel system for the study of TSH β-subunit gene expression in normal rat pituitary cells in vitro.