Proliferative and nutritional dependent regulation of glyceraldehyde-3-phosphate dehydrogenase expression in the rat liver

Cell Prolif. 2002 Jun;35(3):173-82. doi: 10.1046/j.1365-2184.2002.00236.x.

Abstract

Glyceraldehyde-3-phosphate dehydrogenase is a multifunctional protein possessing numerous cytoplasmic and nuclear functions associated with cellular proliferation. Despite the emerging role of glyceraldehyde-3-phosphate dehydrogenase in regulating the proliferative process, there is a paucity of data regarding its expression and intracellular distribution in non-malignant proliferating hepatocytes. Thus the aim of the present study was to document the intracellular distribution of glyceraldehyde-3-phosphate dehydrogenase protein in proliferating hepatocytes derived from regenerating rat livers, and glyceraldehyde-3-phosphate dehydrogenase gene expression in fasted and re-fed rats following partial hepatectomy (PHx). Glyceraldehyde-3-phosphate dehydrogenase mRNA and protein expression were documented by Northern and Western blot analyses, respectively, at various times following 70% PHx in adult Sprague-Dawley rats. At 24 h post-surgery, glyceraldehyde-3-phosphate dehydrogenase mRNA expression was significantly increased in both PHx and sham operated rats (P < 0.001), respectively. Despite the increase in glyceraldehyde-3-phosphate dehydrogenase mRNA expression in both groups, only PHx rats had a significant increase in the nuclear fraction of glyceraldehyde-3-phosphate dehydrogenase protein (threefold increase compared to sham and baseline levels, P < 0.01), cytoplasmic levels of glyceraldehyde-3-phosphate dehydrogenase protein remained unaltered in both groups. In terms of the effects of feeding and fasting on rats there were no significant differences in glyceraldehyde-3-phosphate dehydrogenase mRNA levels, whether fasted or refed, in rats that had undergone PHx, 8 h earlier. On the other hand, glyceraldehyde-3-phosphate dehydrogenase mRNA levels were significantly increased in refed compared to fasted sham operated rats 8 h following surgery. Serum insulin concentrations were higher in the refed PHx and sham groups compared to their fasted counterparts. The results of this study indicate that although glyceraldehyde-3-phosphate dehydrogenase mRNA are altered to the same extent in PHx and sham-operated rats following surgery, increases in the nuclear fraction of glyceraldehyde-3-phosphate dehydrogenase protein only occur in PHx rats. The results also indicate that glyceraldehyde-3-phosphate dehydrogenase expression is affected by the nutritional status of animals undergoing abdominal sham surgery.

MeSH terms

  • Animals
  • Cell Division
  • Cell Nucleus / enzymology
  • Fasting
  • Gene Expression Regulation
  • Glyceraldehyde-3-Phosphate Dehydrogenases / biosynthesis*
  • Glyceraldehyde-3-Phosphate Dehydrogenases / genetics
  • Hepatocytes / enzymology
  • Humans
  • Liver / enzymology*
  • Liver Cirrhosis / enzymology
  • Liver Regeneration
  • Male
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Sprague-Dawley

Substances

  • RNA, Messenger
  • Glyceraldehyde-3-Phosphate Dehydrogenases