Adaptive changes in energy metabolism, as reflected by pyruvate kinase and cytochrome oxidase activities, were examined during in vitro differentiation of the cultivated macrophage. Serum concentrations of tissue culture media, which directly influence endocytic activity, and ambient oxygen tension were both shown to influence pyruvate kinase and cytochrome oxidase activities. Cells maintained in high serum concentrations (30% newborn calf serum [NBCS]) exhibited a 300–400% increase in pyruvate kinase activity and a 40% increase in cytochrome oxidase activity, whereas cells maintained in low serum concentrations (2% NBCS) exhibited a lesser increase (65%) in pyruvate kinase activity and no change in cytochrome oxidase activity. Anaerobiosis resulted in additional alterations in pyruvate kinase and cytochrome oxidase activities. Cells maintained for 48–72 h under anaerobic conditions exhibited a 500–600% increase in pyruvate kinase activity and a 40% decrease in cytochrome oxidase activity. Increased pyruvate kinase activity was dependent on continued protein synthesis. Enzyme increases occurred in anaerobically cultured cells despite an overall reduction in cell protein synthesis. It is suggested that adaptive changes in pyruvate kinase and cytochrome oxidase activity resulting from alterations in either serum concentration or ambient oxygen tension are regulated by two independent mechanisms. One mechanism is aimed at providing energy for endocytic activity and the other in compensating for impaired oxidative metabolism during anaerobiosis.
Article|
December 01 1973
ADAPTATIONS OF ENERGY METABOLISM IN THE CULTIVATED MACROPHAGE
Lawrence M. Simon,
Lawrence M. Simon
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
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Stanton G. Axline,
Stanton G. Axline
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
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Barry R. Horn,
Barry R. Horn
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
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Eugene D. Robin
Eugene D. Robin
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
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Lawrence M. Simon
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
Stanton G. Axline
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
Barry R. Horn
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
Eugene D. Robin
From the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305 and Stanford Medical Service, Veterans Administration Hospital, Palo Alto, California 94304
Received:
August 21 1973
Online ISSN: 1540-9538
Print ISSN: 0022-1007
Copyright © 1973 by The Rockefeller University Press
1973
J Exp Med (1973) 138 (6): 1413–1425.
Article history
Received:
August 21 1973
Citation
Lawrence M. Simon, Stanton G. Axline, Barry R. Horn, Eugene D. Robin; ADAPTATIONS OF ENERGY METABOLISM IN THE CULTIVATED MACROPHAGE . J Exp Med 1 December 1973; 138 (6): 1413–1425. doi: https://doi.org/10.1084/jem.138.6.1413
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