Compartmentation of carbohydrate metabolism in vascular smooth muscle

Ron Lynch, R. J. Paul

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

In vascular smooth muscle, oxidative phosphorylation and glycolysis are independently regulated. Previous studies indicated that the independent regulation of these pathways was related to a compartmentation of carbohydrate metabolism. To further study carbohydrate metabolism, glucose transport and the incorporation of radiolabel from glucose into glycogen and lactate were measured after the oxidative and glycolytic pathways were independently altered. Ouabain stimulated mechanical activity, oxygen consumption, and glycogenolysis, whereas lactate production was decreased. Although glycogenolysis was substantial, glucose was the only substrate for lactate, indicating that intermediates derived from glycogen do not mix with those from glucose uptake. Thus glycogenolysis and glycolysis are carried out by independent enzymatic pathways. Insulin-stimulated lactate production and glucose transport without affecting the other parameters. Again, lactate was produced only from glucose. Phenytoin decreased isometric tension and oxygen consumption, whereas stimulating lactate production and glycogenolysis. Glycogen was the primary substrate for the lactate produced. Our findings indicate that the compartmentation of substrate utilization is ascribable to the coordination of glycogenolysis with increases in oxygen consumption and the coupling of glycolysis to the Na-K-adenosine triphosphatase. The coupling of independent energy providing pathways to specific endergonic processes indicates a mechanism by which cellular energetic efficiency may be optimized.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume252
Issue number3
StatePublished - 1987
Externally publishedYes

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Carbohydrate Metabolism
Vascular Smooth Muscle
Glycogenolysis
Muscle
Lactic Acid
Glucose
Glycolysis
Glycogen
Oxygen Consumption
Oxygen
Substrates
Oxidative Phosphorylation
Phenytoin
Ouabain
Adenosine Triphosphatases
Insulin

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Compartmentation of carbohydrate metabolism in vascular smooth muscle. / Lynch, Ron; Paul, R. J.

In: American Journal of Physiology - Cell Physiology, Vol. 252, No. 3, 1987.

Research output: Contribution to journalArticle

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