REGULATION OF CORTICOTROPIN-RELEASING HORMONE-RECEPTOR TYPE-1 MESSENGER-RNA LEVEL IN Y-79 RETINOBLASTOMA CELLS - POTENTIAL IMPLICATIONS FORHUMAN STRESS-RESPONSE AND IMMUNE INFLAMMATORY REACTION/

WE report the regulation of type 1 receptor mRNA in Y-79 human retinob lastoma cells, grown in the absence or presence of pharmacological lev els of phorbol esters, forskolin, glucocorticoids and their combinatio ns. To control for inducibility and for assessing the sensitivity of t he Y-79 system to glucocorticoids, corticotropin releasing hormone mRN A levels were measured in parallel. All treatments stimulated corticot ropin releasing hormone receptor type I gene expression relative to ba seline. A weak suppression of corticotropin releasing hormone mRNA lev el was observed during dexamethasone treatment. The cell line expresse d ten-fold excess of receptor to Ligand mRNA under basal conditions. T he findings predict the presence of functional phorbol ester, cyclic A MP and glucocorticoid response elements in the promoter region of cort icotropin releasing hormone receptor type I gene and support a potenti al role for its product during chronic stress and immune/inflammatory reaction.