Effect of physical fitness and endurance exercise on indirect biomarkers of growth hormone and insulin misuse: Immunoassay-based measurement in urine samples.

Indirect biomarkers of recombinant human growth hormone (rhGH), insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II), insulin-like growth factor binding proteins (IGFBP-2 and IGFBP-3) and insulin (C-peptide) were measured together with urinary parameters of renal damage (β2-microglobulin and proteinuria) by immunoassays, in house validated for the purpose, in 61 subjects (36 elite athletes, 18 recreational athletes and 7 sedentary individuals) with different levels of physical fitness and endurance exercise.