Protein metabolism in lung: Use of isolated perfused lung to study protein degradation

M. J. Chiang, P. Whitney, D. Massaro

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

This study investigates the use of the isolated perfused lung to study protein degradation. Proteins were labeled in vivo for 10 min or for 5 h using L-[U-14C]phenylalanine. When prelabeled lungs were perfused in vitro virtually all of the acid-soluble and acid-insoluble radioactivity in the tissue and perfusate remained as phenylalanine. Protein degradation was measured as the accumulation of free [14C]phenylalanine in the perfusate; during the time this accumulated the amount of intracellular free phenylalanine and the free phenylalanine space remained constant. Proteins labeled during 10 min had a constant rate of degradation between 45 and 90 min of perfusion (about 11%/h); those labeled during 5h had a constant rate of degradation for 90 min (about 3%/h). The percent dry lung weight did not change during the perfusion. We conclude that measurable rates of proteolysis of 'rapid' and 'slowly' turning over proteins can be obtained while the lung is virtually free of edema. This system should allow studies on the modulation of proteolysis in intact lung under defined conditions.

Original languageEnglish (US)
Pages (from-to)72-78
Number of pages7
JournalJournal of Applied Physiology Respiratory Environmental and Exercise Physiology
Volume47
Issue number1
StatePublished - Jan 1 1979

ASJC Scopus subject areas

  • Physiology
  • Endocrinology

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