The role of intracellular Ca2+ in the regulation of gluconeogenesis.
A hypothesis for the hormonal regulation of gluconeogenesis, in which increases in cytosolic free-Ca2+ levels ([Ca2+]i) play a major role, is presented. This hypothesis is based on the observation that gluconeogenic hormones evoke a common pattern of Ca2+ redistribution, resulting in increases in [Ca2+]i. Current concepts of hormonally evoked Ca2+ fluxes are presented and discussed. It is suggested that the increase in [Ca2+]i is functionally linked to stimulation of gluconeogenesis. The stimulation of gluconeogenesis is accomplished in two ways: (1) by increasing the activities of the Krebs cycle and the electron-transfer chain, thereby supplying adenosine triphosphates (ATP) and reducing equivalents to the process; and (2) by stimulating the activities of key gluconeogenic enzymes, such as pyruvate carboxylase. The hypothesis presents a conceptual framework that ties together two interrelated manifestations of hormone action: signal transduction and metabolism.
Kraus-Friedmann
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Department of Integrative Biology, University of Texas Medical School at Houston, 77225-0708, USA.
Feng
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L
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002395:Catecholamines / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D005934:Glucagon / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D005943:Gluconeogenesis; D006801:Humans; D015398:Signal Transduction; D014667:Vasopressins / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D002395:Catecholamines; D005938:Glucocorticoids; D014667:Vasopressins; D005934:Glucagon; D000242:Cyclic AMP; D002118:Calcium