title: Growth hormone induced increase in serum IGFBP-3 level is reversed by anabolic steroids in substance abusing power athletes.
abstract: OBJECTIVE
  Body builders may use growth hormone (GH) and anabolic steroids to increase fitness and muscle mass. GH increases serum concentrations of IGF-I and IGFBP-3. The combined effects of GH and anabolic androgenic steroids on IGFBP-3 and IGF-I levels are not known under authentic substance-abusing conditions. The aim of this study was to investigate this in substance-abusing power athletes.
  
  
  METHODS
  Nine healthy, non-obese and non-competing male power athletes, all aggressive substance abusers, used GH and/or anabolic steroids independently of this study. Blood samples were taken both during and between the drug intake. Sixteen substance non-abusing wrestlers served as controls.
  
  
  METHODS
  Serum IGF-I concentration was measured by radioimmunoassay and the IGFBP-3 concentration was measured by two immunofluorometric assays, one detecting proteolytic fragments of IGFBP-3. The capacity of serum to proteolytically cleave IGFBP-3 was studied by the proteolysis assay.
  
  
  RESULTS
  While growth hormone increased the IGFBP-3 and IGF-I concentrations, anabolic steroids decreased the same. Concomitant use of growth hormone and anabolic steroids decreased the IGFBP-3 concentration in five out of six abuse periods in spite of the fact that the IGF-I concentration remained elevated in four of them. However, in two men who were on low calorie diet both the IGF-I and IGFBP-3 concentrations decreased during combined GH/anabolic steroid abuse. No proteolytic fragmentation of IGFBP-3 was observed.
  
  
  CONCLUSIONS
  Massive abuse of anabolic steroids decreases both the basal and GH-stimulated IGFBP-3 concentrations, whereas its effects on serum IGF-I concentration are variable and affected by low calorie diet. This study demonstrates that detection of GH doping by measuring the IGF-I and/or IGFBP-3 levels has notable confounding factors.
authors.affiliation: National Public Health Institute, Laboratory of Pharmacology and Toxicology, Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Karila
authors.forename: H
authors.initials: H
authors.lastname: Koistinen
authors.forename: M
authors.initials: M
authors.lastname: Seppälä
authors.forename: R
authors.initials: R
authors.lastname: Koistinen
authors.forename: T
authors.initials: T
authors.lastname: Seppälä
mesh_terms: D000328:Adult; D045930:Anabolic Agents / Q000008:administration & dosage / Q000494:pharmacology; D016022:Case-Control Studies; D018752:Diet, Fat-Restricted; D004347:Drug Interactions; D013006:Growth Hormone / Q000008:administration & dosage / Q000037:antagonists & inhibitors; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection; D019966:Substance-Related Disorders / Q000097:blood*; D014891:Weight Lifting; D014952:Wrestling
chemical_list: D045930:Anabolic Agents; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone