Muscle hypertrophy training does not suppress the GH/IGF axis in young adult males

J Endocrinol Invest. 2023 Dec;46(12):2601-2607. doi: 10.1007/s40618-023-02116-1. Epub 2023 Jun 24.

Abstract

Purpose: This study aimed to analyze the expression of the IGF type-1 receptor gene (IGF-1r) and IGF-I, GH, testosterone, and IGFBP-3 concentrations in young people subjected to 10 weeks of muscle hypertrophy training.

Methods: IGF-1r expression, serum concentrations of IGF-I, IGFBP-3, GH, and total testosterone, as well as body composition, fat percentage, and body mass index, were determined for 22 healthy young males at three moments of resistance training (first, fifth, and tenth week of training).

Results: Throughout the 10 weeks of training, a reduction was observed in the relative expression of the IGF-1r gene (2-ΔΔCT) and an increase in IGF-I and GH concentrations. A reduction in total testosterone concentrations was detected during the recovery period in the fifth week. The IGFBP-3 concentrations did not change throughout the training.

Conclusions: The resistance training protocol prescribed for muscle hypertrophy did not suppress the GH-IGF-I axis, but it did cause alterations in IGF-1r gene expression and in IGF-I kinetics compatible with increased IGF bioactivity.

Keywords: GH/IGF-I axis; Growth; Resistance training.

MeSH terms

  • Adolescent
  • Humans
  • Hypertrophy
  • Insulin-Like Growth Factor Binding Protein 3* / genetics
  • Insulin-Like Growth Factor I* / genetics
  • Insulin-Like Growth Factor I* / metabolism
  • Male
  • Muscles / metabolism
  • Testosterone
  • Young Adult

Substances

  • Insulin-Like Growth Factor Binding Protein 3
  • Insulin-Like Growth Factor I
  • Testosterone