Effect of Trenbolone Acetate on Protein Synthesis and Degradation Rates in Fused Bovine Satellite Cell Cultures

Domest Anim Endocrinol. 2011 Jan;40(1):60-6. doi: 10.1016/j.domaniend.2010.08.007. Epub 2010 Sep 29.

Abstract

Although androgenic and estrogenic steroids are widely used to enhance muscle growth and increase feed efficiency in feedlot cattle, their mechanism of action is not well understood. Although in vivo studies have indicated that androgens affect protein synthesis and protein degradation rate in muscle, results from in vitro studies have been inconsistent. We have examined the effects of trenbolone acetate (TBA), a synthetic androgen, on protein synthesis and degradation rates in fused bovine satellite cell (BSC) cultures. Additionally, we have examined the effects of compounds that interfere with binding of TBA or insulin-like growth factor-1 (IGF-1) to their respective receptors on TBA-induced alterations in protein synthesis and degradation rates in BSC cultures. Treatment of fused BSC cultures with TBA results in a concentration-dependent increase (P < 0.05) in protein synthesis rate and a decrease (P < 0.05) in degradation rate, establishing that TBA directly affects these parameters. Flutamide, a compound that prevents androgen binding to the androgen receptor, suppresses (P < 0.05) TBA-induced alterations in protein synthesis and degradation in fused BSC cultures, indicating the androgen receptor is involved. JB1, a competitive inhibitor of IGF-1 binding to the type 1 IGF receptor (IGF1R), suppresses (P < 0.05) TBA-induced alterations in protein synthesis and degradation, indicating that this receptor also is involved in the actions of TBA on both synthesis and degradation. In summary, our data show that TBA acts directly to alter both protein synthesis and degradation rates in fused BSC cultures via mechanisms involving both the androgen receptor and IGF1R.

Publication types

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

MeSH terms

  • Anabolic Agents / pharmacology*
  • Androgen Antagonists / pharmacology
  • Animals
  • Cattle
  • Cell Fusion
  • Cells, Cultured
  • Flutamide / pharmacology
  • Male
  • Muscle Proteins / biosynthesis*
  • Muscle Proteins / metabolism*
  • Receptor, IGF Type 1 / drug effects
  • Receptor, IGF Type 1 / physiology
  • Receptors, Androgen / drug effects
  • Receptors, Androgen / physiology
  • Satellite Cells, Skeletal Muscle / drug effects
  • Satellite Cells, Skeletal Muscle / metabolism*
  • Trenbolone Acetate / analogs & derivatives*
  • Trenbolone Acetate / pharmacology

Substances

  • Anabolic Agents
  • Androgen Antagonists
  • Muscle Proteins
  • Receptors, Androgen
  • Flutamide
  • Receptor, IGF Type 1
  • Trenbolone Acetate