title: Two-week inhalation of budesonide increases muscle Na,K ATPase content but not endurance in response to terbutaline in men.
abstract: While chronic systemic administration of glucocorticoids increases muscle Na+,K+ATPase content, such effect is unexplored after therapeutic inhalation. We investigated the effect of therapeutic inhalation of the glucocorticoid budesonide on Na+,K+ATPase content of skeletal muscle in men. Ten healthy trained subjects, aged 23 ± 4 years (mean ± 95% CI), participated in the study. Before and after 2 weeks of daily inhalation of budesonide (1.6 mg/day), a biopsy was taken from the vastus lateralis muscle for measurement of Na+,K+ATPase content and blood samples were drawn for determination of plasma budesonide, cortisol, and K+. Subjects' performance during cycling to fatigue at 90% of incremental peak power output (iPPO) was measured in response to 4 mg inhaled terbutaline to maximally stimulate Na+,K+ATPase activity. Plasma concentrations of budesonide rose to 5.0 ± 1.6 nM with the intervention, whereas no changes were observed in plasma cortisol. Muscle Na+,K+ATPase content increased (P ≤ 0.01) by 46 ± 34 pmol/(g wet wt) (17% increase) with the intervention. Cycling performance at 90% of iPPO did not change (P = 0.21) with the intervention (203 vs 214 s) in response to terbutaline. The present observations show that therapeutic inhalation of glucocorticoids increases muscle Na+,K+ATPase content, but does not enhance high-intensity cycling endurance in response to terbutaline.
authors.affiliation: Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark.|Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark.|IOC Sports Medicine Copenhagen, Copenhagen, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Hostrup
authors.affiliation: Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Jessen
authors.affiliation: Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Onslev
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Clausen
authors.affiliation: Department of Respiratory Research, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Porsbjerg
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D001706:Biopsy; D019819:Budesonide / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D010807:Physical Endurance / Q000187:drug effects*; D011188:Potassium / Q000097:blood; D052097:Quadriceps Muscle / Q000187:drug effects* / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013726:Terbutaline / Q000008:administration & dosage / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D019819:Budesonide; D000254:Sodium-Potassium-Exchanging ATPase; D013726:Terbutaline; D011188:Potassium; D006854:Hydrocortisone
keywords: 
  ICS
  ; ATPase; Na+,K+ pump; beta2-adrenergic; doping; glucocorticos-teroids; ion handling; muscle fatigue; physiology