Resistance Training and Testosterone Levels in Male Patients with Chronic Kidney Disease Undergoing Dialysis
Background.We investigated serum testosterone and insulin-like growth factor 1 (IGF-1) levels’ associations with muscle fibre size and resistance training in male dialysis patients.Methods.Male patients were included in a 16-week control period followed by 16 weeks of resistance training thrice weekly. Blood samples were obtained to analyse testosterone, luteinizing hormone (LH), IGF-1, and IGF-binding protein 3. Muscle fibres’ size was analysed in biopsies fromm. vastus lateralis.Results.The patients’ testosterone levels were within the normal range at baseline (n=20) (19.5 (8.2–52.1) nmol/L versus 17.6 (16.1–18.0), resp.) whereas LH levels were higher (13.0 (5.5–82.8) U/L versus 4.3 (3.3–4.6),P<0.001, resp.). IGF-1 and IGF-binding protein 3 levels were higher in the patients compared with reference values (203 (59–590) ng/mL versus 151 (128–276),P=0.014, and 5045 (3370–9370) ng/mL versus 3244 (3020–3983),P<0.001, resp.). All hormone levels and muscle fibre size (n=12) remained stable throughout the study. Age-adjusted IGF-1 was associated with type 1 and 2 fibre sizes (P<0.05).Conclusion.Patients’ total testosterone values were normal due to markedly increased LH values, which suggest a compensated primary insufficiency of the testosterone producing Leydig cell. Even though testosterone values were normal, resistance training was not associated with muscle hypertrophy. This trial is registered withISRCTN72099857.