Effects of elevated glucose concentrations on the metabolism of the aortic wall

J Clin Invest. 1972 Dec;51(12):3114-23. doi: 10.1172/JCI107138.

Abstract

The effects of elevated glucose concentrations on the metabolism of the aortic wall were examined in a preparation of tubular segments of rabbit descending thoracic aorta comprised of intima and media only. Increased medium glucose concentrations (20-50 mm) resulted in increased aortic sorbitol and fructose concentrations and an increased rate of fructose release into the medium. This increased flux through the polyol pathway can be explained as a consequence both of an increased free intracellular glucose concentration and of the kinetic characteristics of the alditol: NADP oxidoreductase and the l-iditol: NAD oxidoreductase isolated and partially purified from rabbit thoracic aorta. Incubation with elevated glucose concentrations for 2 or more hr was also associated with a significant increase in the water content of the tissue without a significant increase in the inulin space. The oxygen uptake of the tissues incubated with elevated glucose concentrations was significantly reduced; this appears to result from a limitation imposed by oxygen diffusion at physiological oxygen tensions. A compensatory increase in glycolysis and an increase in the aortic lactate/pyruvate concentration ratio were also observed. The oxygen uptake and lactate production of tissue incubated with 50 mm glucose could be preserved at rates observed in tissue incubated with a physiological glucose concentration by the addition of 40 mm mannitol to the medium. Aortic intima and media from alloxan-diabetic rabbits also exhibit an increased water content and a decreased rate of oxygen uptake. These observations suggest that elevated ambient glucose concentrations result in significant alterations in the metabolism of aortic intima and media.

MeSH terms

  • Alcohol Oxidoreductases / metabolism
  • Animals
  • Aorta, Thoracic / enzymology
  • Aorta, Thoracic / metabolism*
  • Blood Glucose / metabolism
  • Diabetes Mellitus, Experimental / metabolism
  • Fructose / metabolism
  • Glucose / pharmacology*
  • Glycolysis
  • Hyperglycemia / metabolism
  • In Vitro Techniques
  • Inulin / metabolism
  • Lactates / metabolism
  • Mannitol / pharmacology
  • Oxygen Consumption
  • Pyruvates / metabolism
  • Rabbits
  • Sorbitol / metabolism
  • Water / metabolism

Substances

  • Blood Glucose
  • Lactates
  • Pyruvates
  • Water
  • Fructose
  • Mannitol
  • Sorbitol
  • Inulin
  • Alcohol Oxidoreductases
  • Glucose