Effects of Testosterone on Mixed-Muscle Protein Synthesis and Proteome Dynamics During Energy Deficit

J Clin Endocrinol Metab. 2022 Jul 14;107(8):e3254-e3263. doi: 10.1210/clinem/dgac295.

Abstract

Context: Effects of testosterone on integrated muscle protein metabolism and muscle mass during energy deficit are undetermined.

Objective: The objective was to determine the effects of testosterone on mixed-muscle protein synthesis (MPS), proteome-wide fractional synthesis rates (FSR), and skeletal muscle mass during energy deficit.

Design: This was a randomized, double-blind, placebo-controlled trial.

Setting: The study was conducted at Pennington Biomedical Research Center.

Participants: Fifty healthy men.

Intervention: The study consisted of 14 days of weight maintenance, followed by a 28-day 55% energy deficit with 200 mg testosterone enanthate (TEST, n = 24) or placebo (PLA, n = 26) weekly, and up to 42 days of ad libitum recovery feeding.

Main outcome measures: Mixed-MPS and proteome-wide FSR before (Pre), during (Mid), and after (Post) the energy deficit were determined using heavy water (days 1-42) and muscle biopsies. Muscle mass was determined using the D3-creatine dilution method.

Results: Mixed-MPS was lower than Pre at Mid and Post (P < 0.0005), with no difference between TEST and PLA. The proportion of individual proteins with numerically higher FSR in TEST than PLA was significant by 2-tailed binomial test at Post (52/67; P < 0.05), but not Mid (32/67; P > 0.05). Muscle mass was unchanged during energy deficit but was greater in TEST than PLA during recovery (P < 0.05).

Conclusions: The high proportion of individual proteins with greater FSR in TEST than PLA at Post suggests exogenous testosterone exerted a delayed but broad stimulatory effect on synthesis rates across the muscle proteome during energy deficit, resulting in muscle mass accretion during subsequent recovery.

Trial registration: ClinicalTrials.gov NCT02734238.

Keywords: anabolism; dynamic proteomics; fractional synthesis rates; heavy water; negative energy balance; translational capacity.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Double-Blind Method
  • Energy Metabolism* / drug effects
  • Humans
  • Male
  • Muscle Proteins* / biosynthesis
  • Muscle, Skeletal* / drug effects
  • Muscle, Skeletal* / metabolism
  • Polyesters / metabolism
  • Polyesters / pharmacology
  • Proteome* / metabolism
  • Testosterone / administration & dosage
  • Testosterone / analogs & derivatives*
  • Testosterone / pharmacology

Substances

  • Muscle Proteins
  • Polyesters
  • Proteome
  • Testosterone
  • testosterone enanthate

Associated data

  • ClinicalTrials.gov/NCT02734238

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