Assessment of immune function after short-term administration of recombinant human growth hormone in healthy young males

Growth hormone (GH) is a commonly used drug aimed at improving sport performance. The aim of this study is to evaluate the immunomodulatory effects of short-term administration of recombinant GH (rhGH) in healthy young males. NK cell number, activity and phenotype, T cell number, CD⁴⁺ (Th1/Th2) cytokine production of IL2, IL4, IL6, IL10, TNF-α and IFN-γ and CD⁴⁺/CD⁸⁺ ratio with particular attention to the possible correlation to IGF-I production were investigated. 30 males (27 ± 9 years) were randomly assigned to placebo (n = 15) or drug (rhGH) 1 mg/day groups data were generated at baseline and days 8, 15, 22 and 29 post injection. Data analysis used General Linear Model with repeated measures, Bonferroni correction factor and signiWcance at p ≤ 0.05. Serum IGF-I levels (ng/mL) increased signiWcantly (p ≤ 0.01) on day 8 (0.48 ± 0.78) after injections compared to baseline (0.31 ± 0.07) and days 15 (0.33 ± 0.06), 22 (0.29 ± 0.05) and 29 (.29 ± 0.06). A signiWcant time eVect was noted in IL10 secretion (pg/mL) from day 15 (P = 35.14 ± 19.93, rhGH = 26.63 ± 16.39) to days 22 (P = 61.32 ± 20.41, rhGH = 74.99 ± 46.91) and 29 (P = 101.98 ± 67.25, rhGH = 107.74; ± 122.58). There was no correlation between IGF-I and NK activity, phenotype or number along with Tlymphocyte number, CD⁴⁺/CD⁸⁺ ratio or Th1 and Th2 cytokine production. In conclusion, cytokine secretion spectrum was not aVected by short-term rhGH administration in young males