title: Stimulation of catecholamine biosynthesis via the protein kinase C pathway by endothelin-1 in PC12 rat pheochromocytoma cells.
abstract: It has been reported that endothelins (ETs) stimulate catecholamine release from chromaffin cells. However, it is not known whether ETs also affect catecholamine biosynthesis. Thus, using a rat pheochromocytoma cell line, PC12, we examined the effects of ETs on catecholamine biosynthesis. The mRNA level and activity of tyrosine hydroxylase (TH), a rate-limiting enzyme in catecholamine biosynthesis, were increased significantly by endothelin-1 (ET-1) (100nM). These stimulatory effects were inhibited completely by a blocker for the A-type endothelin receptor, BQ-123 [cyclo(D-alpha-aspartyl-L-prolyl-D-valyl-L-leucyl-D-tryptophyl)] (1 microM), but not by a blocker for the B-type endothelin receptor, BQ-788 (N-cis 2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarbonyltryptophanyl-D-norleucine (1 microM). Also, Ro-32-0432 (3-[8-[(dimethylamino)methyl]-6,7,8,9-tetrahydropyrido-[1,2-a]indol-10-yl]-4-(1-methyl-3-indolyl)-H-pyrrole-2,5-dione hydrochloride) (100nM), a protein kinase C inhibitor, completely inhibited ET-1-induced increases in TH activity and mRNA level. Furthermore, ET-1 (100nM) significantly stimulated protein kinase C activity, as well as inositol 1,4,5-triphosphate production; these stimulatory effects were abolished by BQ-123 but not by BQ-788. Moreover, ET-1 (100nM) significantly increased both the TH-protein level and the intracellular catecholamine content. By contrast to ET-1, endothelin-3 did not affect catecholamine synthesis. These results indicate that ET-1, but not ET-3, stimulates catecholamine synthesis through the PKC pathway in PC12 cells. Also, the use of selective ET receptor antagonists suggests that the effects of ET-1 on catecholamine biosynthesis are mediated through ET(A).
authors.affiliation: Department of Clinical Pathology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, 305-8575, Ibaraki, Japan. k-takemd@md.tsukuba.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takekoshi
authors.forename: Kiyoaki
authors.initials: K
authors.lastname: Ishii
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Shibuya
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Isobe
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakai
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000378:metabolism; D019332:Endothelin-1 / Q000494:pharmacology*; D019334:Endothelin-3 / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D016716:PC12 Cells; D010673:Pheochromocytoma / Q000473:pathology; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D014407:Tumor Cells, Cultured; D014446:Tyrosine 3-Monooxygenase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D019332:Endothelin-1; D019334:Endothelin-3; D012333:RNA, Messenger; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D014446:Tyrosine 3-Monooxygenase; D011493:Protein Kinase C