A method is described for measuring rates of mitochondrial pyruvate carboxylation in hepatocytes treated with the polyene antibiotic, filipin, to render the plasma membrane permeable to substrates. With this approach it was possible to demonstrate that treatment of cells with glucagon or catecholamines results in a stimulation of mitochondrial CO2 fixation measured in situ comparable with that observed in the isolated mitochondria, in terms of time of onset of the response, hormone selectivity and sensitivity. In addition, angiotensin II and vasopressin were shown to enhance the activity of pyruvate carboxylase in both the intact mitochondria and filipin-treated cells, thus strengthening the postulate that this site is a major locus of hormone action in the control of gluconeogenesis. Addition of 3-mercaptopicolinic acid, to inhibit gluconeogenesis at the level of phosphoenolpyruvate carboxykinase, had no significant effect on the stimulation of pyruvate carboxylation by adrenaline, suggesting that the effect of the hormone at this site is independent of changes in activity of other enzymes further on in the pathway. The data presented preclude the possibility that acute effects of hormones on mitochondrial metabolism are solely artifacts of the preparation procedure.
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May 1983
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Research Article|
May 15 1983
Hormonal stimulation of mitochondrial pyruvate carboxylation in filipin-treated hepatocytes
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1983 London: The Biochemical Society
1983
Biochem J (1983) 212 (2): 417–426.
Citation
E H Allan, A B Chisholm, M A Titheradge; Hormonal stimulation of mitochondrial pyruvate carboxylation in filipin-treated hepatocytes. Biochem J 15 May 1983; 212 (2): 417–426. doi: https://doi.org/10.1042/bj2120417
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