title: Endurance exercise modulates levodopa induced growth hormone release in patients with Parkinson's disease.
abstract: Acute levodopa (LD) application and exercise release human growth hormone (GH). An earlier trial showed, that combined stimulus of exercise and LD administration is the best provocative test for GH response in healthy participants. Objective was to show this combined effect of LD application and exercise on GH response and to investigate the impact on LD metabolism in 20 previously treated patients with Parkinson's disease (PD). We measured GH- and LD plasma concentrations following soluble 200 mg LD/50 mg benserazide administration during endurance exercise and rest on two separate consecutive days. GH concentrations significantly increased on both days, but GH release was significantly delayed during rest. LD metabolism was not altered due to exercise in a clinical relevant manner. Exercise induced a significant faster LD stimulated GH release in comparison with the rest condition. We did not find the supposed increase of LD induced GH release by endurance exercise. We assume, that only a limited amount of GH is available for GH release in the anterior pituitary following an acute 200 mg LD administration. GH disposal also depends on growth hormone releasing hormone (GHRH), which is secreted into hypothalamic portal capillaries. During the exercise condition, the resulting higher blood pressure supports blood flow and thus GHRH transport towards the GH producing cells in the pituitary. This might additionally have caused the significant faster GH release during exercise.
authors.affiliation: Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstrasse 56, 44791 Bochum, Germany. thomas.mueller@ruhr-uni-bochum.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.forename: Jacub
authors.initials: J
authors.lastname: Welnic
authors.forename: Dirk
authors.initials: D
authors.lastname: Woitalla
authors.forename: Siegfried
authors.initials: S
authors.lastname: Muhlack
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000494:pharmacology; D001545:Benserazide / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004357:Drug Synergism; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000187:drug effects; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007980:Levodopa / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood / Q000503:physiopathology* / Q000628:therapy*; D005082:Physical Exertion; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism
chemical_list: D000978:Antiparkinson Agents; D007987:Gonadotropin-Releasing Hormone; D007980:Levodopa; D001545:Benserazide; D013006:Growth Hormone