ISSN:
1573-4919
Keywords:
hyperplasia
;
hypertrophy
;
liver
;
nucleic-acid concentration
;
protein-growth rate
;
protein-turnover rate
;
rainbow trout (Oncorhynchus mykiss)
;
starvation/re-feeding cycle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
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 (AS) also fell, whilst the fractional protein-synthesis rate (KS) remained unchanged and the fractional protein-degradation rate (KD) 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 (KG, AG) rose sharply, as did KS, AS, KD, protein-synthesis efficiency (KRNA) and the protein-synthesis rate/DNA unit (KDNA). 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006953917697
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