Selective changes in the protein-turnover rates and nature of growth induced in trout liver by long-term starvation followed by re-feeding

Mol Cell Biochem. 1999 Nov;201(1-2):1-10. doi: 10.1023/a:1006953917697.

Abstract

We report upon the effects of a cycle of long-term starvation followed by re-feeding on the liver-protein turnover rates and nature of protein growth in the rainbow trout (Oncorhynchus mykiss). We determined the protein-turnover rate and its relationship with the nucleic-acid concentrations in the livers of juvenile trout starved for 70 days and then re-fed for 9 days. During starvation the total hepatic-protein and RNA contents decreased significantly and the absolute protein-synthesis rate (A(S)) also fell, whilst the fractional protein-synthesis rate (K(S)) remained unchanged and the fractional protein-degradation rate (K(D)) increased significantly. Total DNA content, an indicator of hyperplasia, and the protein:DNA ratio, an indicator of hypertrophy, both fell considerably. After re-feeding for 9 days the protein-accumulation rates (K(G), A(G)) rose sharply, as did K(S), A(S), K(D)), protein-synthesis efficiency (K(RNA)) and the protein-synthesis rate/DNA unit (K(DNA)). The total hepatic protein and RNA contents increased but still remained below the control values. The protein:DNA and RNA:DNA ratios increased significantly compared to starved fish. These changes demonstrate the high response capacity of the protein-turnover rates in trout liver upon re-feeding after long-term starvation. Upon re-feeding hypertrophic growth increased considerably whilst hyperplasia remained at starvation levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Animals
  • Cell Division
  • DNA / analysis
  • DNA / biosynthesis
  • Eating
  • Hepatomegaly / metabolism
  • Hyperplasia / metabolism
  • Liver / cytology
  • Liver / metabolism*
  • Liver / pathology*
  • Oncorhynchus mykiss / physiology*
  • Proteins / metabolism*
  • RNA / analysis
  • RNA / biosynthesis
  • Reference Values
  • Starvation / metabolism*
  • Time Factors

Substances

  • Proteins
  • RNA
  • DNA