Complete suppression of protein synthesis during anoxia with no post-anoxia protein synthesis debt in the red-eared slider turtle Trachemys scripta elegans

J Exp Biol. 2001 Dec;204(Pt 24):4353-60.

Abstract

Two previous studies of the effects of anoxia on protein synthesis in anoxia-tolerant turtles (Trachemys scripta elegans, Chrysemys picta bellii) have generated opposing results. Using the flooding-dose method, we measured the rate of protein synthesis following injection and incorporation of a large dose of radiolabelled phenylalanine to resolve the question of whether anoxia results in a downregulation of protein synthesis. After 1 h of anoxia, levels of protein-incorporated radiolabel indicated that protein synthesis rates in the intestine, heart, liver, brain, muscle and lungs were not significantly different from those of normoxic controls. However, from 1 to 6 h of anoxia, quantities of protein-incorporated radiolabel did not increase, suggesting that protein synthesis had ceased or had decreased below a measurable level. There was also no significant post-anoxia increase in protein synthesis rates above normoxic control levels during 3 h of recovery from anoxia. RNA-to-protein ratios did not change significantly in any tissue except the heart, in which RNA levels decreased below normoxic control levels after 6 h of anoxia. Except in the heart, downregulation of protein synthesis during anoxia does not appear to be mediated by changes in tissue RNA concentration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Intestinal Mucosa / metabolism
  • Kinetics
  • Liver / metabolism
  • Lung / metabolism
  • Muscles / metabolism
  • Myocardium / metabolism
  • Oxygen / administration & dosage*
  • Phenylalanine / administration & dosage
  • Protein Biosynthesis*
  • RNA / analysis
  • Tritium
  • Turtles / metabolism*

Substances

  • Tritium
  • Phenylalanine
  • RNA
  • Oxygen