Fibroblast growth factor stabilizes ribonucleic acid and regulates differentiated functions in a multipeptide-secreting neuroendocrine cell line

Abstract

A clonal cell line (44-2C) which synthesizes and secretes somatostatin, neurotensin, calcitonin (CT), and CT gene-related peptide and transiently expresses c-fos was used to characterize the mechanism of action of basic fibroblast growth factor (bFGF). bFGF had two modes of action: 1) short term incubation of 44-2C cells with bFGF increased the cellular content of neurotensin, somatostatin, and CT; and 2) bFGF enhanced the response of the cells to rat hypothalamic GRF-mediated cAMP efflux. The long term action of bFGF was manifested by the permissive effect of the molecule. bFGF had a sustained effect on RNA synthesis, and pretreatment with bFGF for 24 h altered the time course of response of the cells to rat GRF. In this cell line the cellular action of bFGF was not mediated via protein kinase-C action. bFGF was not mitogenic in 44-2C cells. bFGF stimulated uridine incorporation without affecting thymidine incorporation. Results obtained with actinomycin-D and alpha-amanitin suggest that the above effects of bFGF can be correlated with increased RNA stability produced by bFGF.