ADRENOMEDULLIN INDUCES EXPRESSION OF C-FOS AND AP-1 ACTIVITY IN RAT VASCULAR SMOOTH-MUSCLE CELLS AND CARDIOMYOCYTES

The recently described hypotensive peptide adrenomedullin has been sho wn to activate various second messenger pathways in cells of the cardi ovascular system though no genomic actions have yet been described. In cultured rat vascular smooth muscle cells, cardiomyocytes, and cardia c fibroblasts, adrenomedullin caused a rapid, but transient induction of c-fos mRNA expression in all three cell types that varied in magnit ude. Adrenomedullin increased AP-1 DNA binding activities in vascular smooth muscle cells and cardiomyocytes, but not in cardiac fibroblasts . These data suggest that cardiomyocytes and vascular smooth muscle ce lls may be important genomic targets for this novel hormone. (C) 1995 Academic Press, Inc.