title: Induction of astrocyte argininosuccinate synthetase and argininosuccinate lyase by dibutyryl cyclic AMP and dexamethasone.
abstract: Arginine is an intermediate in the elimination of excess nitrogen and is the substrate for nitric oxide synthesis. Arginine synthesis has been reported in brain tissue. We have studied the activity of the arginine biosynthetic enzymes argininosuccinate synthetase and argininosuccinate lyase in dexamethasone and/or dibutyryl cyclic AMP treated rat astrocyte cultures. Argininosuccinate lyase activity was stimulated by treatment with either effector and an additive effect was obtained when both agents were added simultaneously. Argininosuccinate synthetase was also increased in dexamethasone treated astrocytes. The effect of dibutyryl cyclic AMP on argininosuccinate synthetase was variable, suggesting a role for additional factors in its regulation as compared to argininosuccinate lyase. Regulation of arginine synthesis in astrocytes may be important to insure that arginine is not limiting for nitric oxide synthesis in neural tissue.
authors.affiliation: Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, USA. mjackson@umabnet.ab.umd.edu
authors.forename: M J
authors.initials: MJ
authors.lastname: Jackson
authors.forename: H R
authors.initials: HR
authors.lastname: Zielke
authors.forename: C L
authors.initials: CL
authors.lastname: Zielke
mesh_terms: D000262:Adenylyl Cyclases / Q000096:biosynthesis; D000818:Animals; D000831:Animals, Newborn; D001123:Argininosuccinate Lyase / Q000096:biosynthesis*; D001124:Argininosuccinate Synthase / Q000096:biosynthesis*; D001253:Astrocytes / Q000187:drug effects* / Q000201:enzymology; D003994:Bucladesine / Q000494:pharmacology*; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D004790:Enzyme Induction; D005934:Glucagon / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D051381:Rats; D015203:Reproducibility of Results
chemical_list: D005938:Glucocorticoids; D003994:Bucladesine; D003907:Dexamethasone; D005934:Glucagon; D001123:Argininosuccinate Lyase; D000262:Adenylyl Cyclases; D001124:Argininosuccinate Synthase