Long-term regulation of catecholamine formation by ouabain in cultured bovine adrenal chromaffin cells.
The long-term effects of ouabain, an inhibitor of Na+/K+ -ATPase, on catecholamine formation in cultured bovine adrenal chromaffin cells were examined. The increase in [14C]catecholamine formation from [14C]tyrosine induced by ouabain was dependent on incubation time, and its maximal effect was observed after incubation for 8 h. The stimulatory effect of ouabain was concentration dependent (10-300 nM), causing maximal stimulation at 300 nM. The formation of [14C]catecholamines induced by ouabain was not increased by incubation with [14C]DOPA instead of [14C]tyrosine. Ouabain-induced [14C]catecholamine formation was influenced by decreases in extracellular Ca2+ concentration, but not by the presence of cycloheximide or actinomycin D. These results suggested that ouabain stimulates continuous activation of hydroxylation of tyrosine through a Ca2+ -dependent mechanism in cultured bovine adrenal chromaffin cells.
Ozawa
Y
Y
Department of Pharmacy, Tokushima University Hospital, Japan.
Houchi
H
H
Teraoka
K
K
Azuma
M
M
Kamimura
T
T
Yoshizumi
M
M
Tsuchiya
K
K
Tamaki
T
T
Minakuchi
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000096:biosynthesis*; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D014443:Tyrosine / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000502:physiology
D002395:Catecholamines; D004791:Enzyme Inhibitors; D014443:Tyrosine; D010042:Ouabain; D014446:Tyrosine 3-Monooxygenase; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium