title: Effects of aerobic exercise on ectopic lipids in patients with growth hormone deficiency before and after growth hormone replacement therapy.
abstract: Growth hormone replacement therapy (GHRT) increases exercise capacity and insulin resistance while it decreases fat mass in growth hormone-deficient patients (GHD). Ectopic lipids (intramyocellular (IMCL) and intrahepatocellular lipids (IHCL) are related to insulin resistance. The effect of GHRT on ectopic lipids is unknown. It is hypothesized that exercise-induced utilization of ectopic lipids is significantly decreased in GHD patients and normalized by GHRT. GHD (4 females, 6 males) and age/gender/waist-matched control subjects (CS) were studied. VO2max was assessed on a treadmill and insulin sensitivity determined by a two-step hyperinsulinaemic-euglycaemic clamp. Visceral (VAT) and subcutaneous (SAT) fat were quantified by MR-imaging. IHCL and IMCL were measured before and after a 2 h exercise at 50-60% of VO2max using MR-spectroscopy (∆IMCL, ∆IHCL). Identical investigations were performed after 6 months of GHRT. VO2max was similar in GHD and CS and significantly increased after GHRT; GHRT significantly decreased SAT and VAT. 2 h-exercise resulted in a decrease in IMCL (significant in CS and GHRT) and a significant increase in IHCL in CS and GHD pre and post GHRT. GHRT didn't significantly impact on ∆IMCL and ∆IHCL. We conclude that aerobic exercise affects ectopic lipids in patients and controls. GHRT increases exercise capacity without influencing ectopic lipids.
authors.affiliation: Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital of Bern, Inselspital, CH-3010 Bern, Switzerland.
authors.forename: Emanuel R
authors.initials: ER
authors.lastname: Christ
authors.affiliation: Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital of Bern, Inselspital, CH-3010 Bern, Switzerland.|Department of Internal Medicine, University Hospital of Basel, CH-4056 Basel, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Egger
authors.affiliation: Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital of Bern, Inselspital, CH-3010 Bern, Switzerland.
authors.forename: Sabin
authors.initials: S
authors.lastname: Allemann
authors.affiliation: Department of Clinical Research, Division of MR-Spectroscopy and Methodology, University of Bern, Inselspital, CH-3010 Bern, Switzerland.
authors.forename: Tania
authors.initials: T
authors.lastname: Buehler
authors.affiliation: Department of Clinical Research, Division of MR-Spectroscopy and Methodology, University of Bern, Inselspital, CH-3010 Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Kreis
authors.affiliation: Department of Clinical Research, Division of MR-Spectroscopy and Methodology, University of Bern, Inselspital, CH-3010 Bern, Switzerland.
authors.forename: Chris
authors.initials: C
authors.lastname: Boesch
mesh_terms: D000328:Adult; D001786:Blood Glucose; D004393:Dwarfism, Pituitary / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism* / Q000628:therapy*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D005947:Glucose / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D020249:Hormone Replacement Therapy; D019382:Human Growth Hormone / Q000172:deficiency*; D006801:Humans; D007333:Insulin Resistance; D050152:Intra-Abdominal Fat / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D032342:Muscle Cells / Q000378:metabolism; D011446:Prospective Studies; D050151:Subcutaneous Fat / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D019382:Human Growth Hormone; D005947:Glucose