title: Cell cycle-dependent modulation of biosynthesis and stimulus-evoked release of catecholamines in PC12 pheochromocytoma cells.
abstract: Catecholamine biosynthesis and its stimulus-evoked release in PC12 pheochromocytoma cells were studied as a function of cell cycle by means of HPLC with electrochemical detection. We found that 3,4-dihydroxyphenylethylamine (dopamine) levels in PC12 cells remained constant throughout the period of cell cycle. In contrast, the noradrenaline content was dependent on the cell cycle: it increased during the S + G2 phase followed by a decrease in the M phase. These results were confirmed further by measuring the activities catalyzing the catecholamine biosynthesis. Thus, activities of tyrosine 3-monooxygenase and 3,4-dihydroxyphenylalanine decarboxylase were independent of the cell cycle, whereas both soluble and membrane-bound dopamine beta-monooxygenase activities were modulated during the cell cycle. On the other hand, release of the catecholamines stimulated with 50 mM KCl increased in the G1 phase, reached a maximum in the late G1, and then gradually decreased in later periods. We also found that carbamylcholine-induced release of the catecholamines occurred maximally in the early S + G2 phase followed by a decrease during the M phase. Cell cycle dependence of the catecholamine release was in good agreement with that of 45Ca2+ uptake. Thus, this study provides evidence that the catecholamine biosynthesis and its release in PC12 cells are modulated during the period of cell cycle.
authors.forename: T
authors.initials: T
authors.lastname: Koike
authors.forename: A
authors.initials: A
authors.lastname: Takashima
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism*; D002453:Cell Cycle; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D004296:Dopa Decarboxylase / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism; D007399:Interphase; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism; D010673:Pheochromocytoma / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D002395:Catecholamines; D002217:Carbachol; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D004296:Dopa Decarboxylase; D011188:Potassium; D002118:Calcium; D004298:Dopamine; D009638:Norepinephrine