Effect of ethanol on the synthesis and secretion of hepatic secretory glycoproteins and albumin

D. J. Tuma, R. B. Jennett, Michael Floyd Sorrell

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Abstract

The effects of ethanol on the synthesis and secretion of serum glycoproteins and albumin, a nonglycosylated protein, were studied in rat liver slices. Serum glycoproteins and albumin were determined by immunoprecipitation from either the incubation medium or from the washed slices. When ethanol (10 mM) was present in the incubation medium, [14C]glucosamine incorporation in secretory glycoproteins was decreased. This inhibitory effect was, however, much greater in the secretory proteins released into the medium than in those retained in the liver slices. Similar inhibitions by ethanol were also observed when leucine or valine were used as a label for either total export proteins or albumin. Since ethanol impaired protein synthesis, an inhibitor of protein synthesis, cycloheximide, was used so that both the control and ethanol‐treated slices had identical pools of protein acceptors available for glycosylation. When cycloheximide alone was added to the slices, glucosamine radioactivity of secretory glycoproteins was equally reduced in both the medium and the liver. When cycloheximide and ethanol were both present, decreased appearance of glucosamine‐labeled proteins in the medium was observed when compared to the slices containing cycloheximide alone; however, radioactivity of secretory glycoproteins retained in the liver was elevated. Ethanol also decreased the appearance of fucose‐labeled glycoproteins in the medium without altering fucose incorporation into the total pool of secretory glycoproteins. The effects of ethanol on hepatic protein secretion independent of its effect on synthesis were further determined by prelabeling proteins with either [14C]leucine or [14C]fucose. Ethanol impaired the secretion of these prelabeled proteins into the medium. The results of this study show that ethanol impairs both the synthesis and secretion of secretory glycoproteins and albumin.

Original languageEnglish (US)
Pages (from-to)590-598
Number of pages9
JournalHepatology
Volume1
Issue number6
DOIs
StatePublished - Jan 1 1981

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Albumins
Glycoproteins
Ethanol
Liver
Cycloheximide
Proteins
Fucose
Glucosamine
Serum Albumin
Leucine
Radioactivity
Protein Synthesis Inhibitors
Valine
Glycosylation
Immunoprecipitation

ASJC Scopus subject areas

  • Hepatology

Cite this

Effect of ethanol on the synthesis and secretion of hepatic secretory glycoproteins and albumin. / Tuma, D. J.; Jennett, R. B.; Sorrell, Michael Floyd.

In: Hepatology, Vol. 1, No. 6, 01.01.1981, p. 590-598.

Research output: Contribution to journalArticle

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