Reduction of dopamine beta-hydroxylase gene expression by calcium in bovine chromaffin cells.
We determined the effect of Ca++ influx on dopamine beta-hydroxylase (DBH) gene expression in primary cultured bovine chromaffin cells. The Ca++ ionophore A23187 (100nM) specifically reduced DBH mRNA to 15 +/- 10% of the untreated control while tyrosine hydroxylase was induced (142 +/- 15%) and phenylethanolamine N-methyltransferase was unchanged (107 +/- 11%). This effect on DBH was also observed with ionomycin, reversed by EGTA and unaffected by cycloheximide. Depolarization by potassium also resulted in DBH reduction which was reversed by the voltage dependent Ca++ channel blockers nifedipine and verapamil. DBH mRNA level reduced by A23187 could be re-induced by forskolin and DBH induced by forskolin could be reduced by the ionophore, suggesting that the cAMP and Ca++ pathways might act independently in regulating DBH gene expression.
Hwang
O
O
Department of Biochemistry, University of Ulsan College of Medicine, Seoul, Korea.
Lee
J D
JD
D000818:Animals; D001692:Biological Transport; D015152:Blotting, Northern; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D004299:Dopamine beta-Hydroxylase / Q000096:biosynthesis / Q000235:genetics*; D004533:Egtazic Acid / Q000494:pharmacology; D004790:Enzyme Induction; D005786:Gene Expression Regulation; D015759:Ionomycin / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis / Q000235:genetics
D002121:Calcium Channel Blockers; D012333:RNA, Messenger; D005576:Colforsin; D000001:Calcimycin; D004533:Egtazic Acid; D015759:Ionomycin; D003513:Cycloheximide; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D002118:Calcium