Osmotic alterations of the lysosomal system during rat liver perfusion: Reversible suppression by insulin and amino acids

Alice N. Neely, Paul Nelson, Gleen E. Mortimore

Research output: Contribution to journalArticle

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Abstract

Livers from nonfasted rats were perfused in situ under conditions known from previous studies in this laboratory to increase or decrease overall endogenous proteolysis. At the termination of the experiments, lysosomal alterations were evaluated by the increase in free acid phosphatase or N-acetyl-β-D-glucosaminidase that occurred when tissue homogenates were subjected to osmotic shock in hypotonic sucrose. In control perfusions, osmotic sensitivity increased spontaneously over unperfused values, reaching maximum by 60 min or earlier. Additions of insulin, amino acid mixtures, or cycloheximide in amounts known to suppress proteolysis prevented this spontaneous perfusion effect or, when added at 60 min, rapidly reversed it. Glucagon alone during perfusion did not increase osmotic sensitivity further; however, stimulation with glucagon was observed when the perfusion effect was suppressed by insulin or cycloheximide. Anoxia, induced by gassing with nitrogen instead of oxygen, markedly reduced the perfusion effect and also doubled the amount of free acid phosphatase in the initial isotonic homogenates. Total acid phosphatase activities in the perfusion experiments were not significantly different from unperfused values and, with the exception of the anoxia perfusions, the amounts of free enzyme present in the initial isotonic sucrose homogenates did not change.

Original languageEnglish (US)
Pages (from-to)458-472
Number of pages15
JournalBBA - General Subjects
Volume338
Issue number2
DOIs
StatePublished - Feb 28 1974

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Acid Phosphatase
Liver
Proteolysis
Rats
Perfusion
Insulin
Cycloheximide
Glucagon
Amino Acids
Sucrose
Hexosaminidases
Nitrogen
Experiments
Tissue
Oxygen
Enzymes
Osmotic Pressure

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology

Cite this

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Osmotic alterations of the lysosomal system during rat liver perfusion : Reversible suppression by insulin and amino acids. / Neely, Alice N.; Nelson, Paul; Mortimore, Gleen E.

In: BBA - General Subjects, Vol. 338, No. 2, 28.02.1974, p. 458-472.

Research output: Contribution to journalArticle

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