title: Growth hormone (GH) responses to arginine and L-dopa alone and after GHRH pretreatment.
abstract: In order to investigate the mechanisms by which arginine and L-dopa cause GH release in humans we measured the GH response to GHRH 1-44 (200 micrograms i.v.), arginine (30 g i.v. over 30 min) and L-dopa (500 mg orally) administered alone and 120 minutes following pretreatment with GHRH 1-44 (200 micrograms i.v.) in normal male subjects. Prior GHRH administration abolished the GH response to subsequent GHRH. Arginine infusion induced a rise in GH levels maximal at 45 min. Following GHRH pretreatment the GH response to arginine was enhanced, with peak values of 19.3 +/- 6.4 vs 53.3 +/- 16.5 mU/l (mean +/- SEM) respectively (P less than 0.02). L-dopa alone induced a rise in GH levels maximal at 90 min (17.6 +/- 7.4 mU/l, mean +/- SEM) but this rise was abolished by pretreatment with GHRH.
authors.affiliation: Department of Medicine, University of Wales College of Medicine, Health Park, Cardiff, UK.
authors.forename: M D
authors.initials: MD
authors.lastname: Page
authors.forename: C
authors.initials: C
authors.lastname: Dieguez
authors.forename: R
authors.initials: R
authors.lastname: Valcavi
authors.forename: C
authors.initials: C
authors.lastname: Edwards
authors.forename: R
authors.initials: R
authors.lastname: Hall
authors.forename: M F
authors.initials: MF
authors.lastname: Scanlon
mesh_terms: D000328:Adult; D001120:Arginine / Q000494:pharmacology*; D004357:Drug Synergism; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007980:Levodopa / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D011388:Prolactin / Q000097:blood
chemical_list: D007980:Levodopa; D011388:Prolactin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine