Regulation of gluconeogenesis and lipogenesis. The regulation of mitochondrial pyruvate metabolism in guinea-pig liver synthesizing precursors for gluconeogenesis.

Content Provider	Semantic Scholar
Author	Somberg, E. W.
Copyright Year	1969
Abstract	1. The carboxylation of pyruvate to oxaloacetate by pyruvate carboxylase in guinea-pig liver mitochondria was determined by measuring the amount of (14)C from H(14)CO(3) (-) fixed into organic acids in the presence of pyruvate, ATP, Mg(2+) and P(i). The main products of pyruvate carboxylation were malate, fumarate and citrate. Pyruvate utilization, metabolite formation and incorporation of (14)C from H(14)CO(3) (-) into these metabolites in the presence and the absence of ATP were examined. The synthesis of phosphoenolpyruvate from pyruvate and bicarbonate is minimal during continued oxidation of pyruvate. Larger amounts of phosphoenolpyruvate are formed from alpha-oxoglutarate than from pyruvate. Addition of glutamate, alpha-oxoglutarate or fumarate did not appreciably increase formation of phosphoenolpyruvate when pyruvate was used as substrate. With alpha-oxoglutarate as substrate addition of fumarate resulted in increased formation of phosphoenolpyruvate, whereas addition of succinate inhibited phosphoenolpyruvate formation. In the presence of added oxaloacetate guinea-pig liver mitochondria synthesized phosphoenolpyruvate in amount sufficiently high to play an appreciable role in gluconeogenesis. 2. Addition of fatty acids of increasing carbon chain length caused a strong inhibition of pyruvate oxidation and phosphoenolpyruvate formation, and greatly promoted carbon dioxide fixation and malate, citrate and acetoacetate accumulation. The incorporation of (14)C from H(14)CO(3) (-), [1-(14)C]pyruvate and [2-(14)C]pyruvate into organic acids formed was examined. 3. It is concluded that guinea-pig liver pyruvate carboxylase contributes significantly to gluconeogenesis and that fatty acids and metabolites play an important role in its regulation.
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Alternate Webpage(s)	http://www.biochemj.org/content/ppbiochemj/112/4/435.full.pdf
PubMed reference number	5801676v1
Volume Number	112
Issue Number	4
Journal	The Biochemical journal
Language	English
Access Restriction	Open
Subject Keyword	Acetoacetates Adenosine Triphosphate Adipogenesis Bicarbonates Fatty Acids Fatty Liver Fumarates Gluconeogenesis Glutamic Acid Large Metabolite Mitochondria, Liver Mitochondrial Inheritance Organic acid (substance) Oxaloacetates PC gene PYRUVATE CARBOXYLASE Pyruvate Metabolism Pathway Pyruvates Succinates alpha-Mannosidosis alpha-ketoglutarate carbon dioxide fixation malate pyruvate oxidation sodium citrate type I interferon receptor
Content Type	Text
Resource Type	Article