The Effect of Epinephrine on Oxygen Consumption, Overall Energy Metabolism, and Substrate Utilization in Rats
In the past 25 years the relationship between plasma free fatty acids (FFA) and glucose metabolism has been studied extensively (Wolfe et al., 1988). In several studies an invers relationship between the availability of FFA and the rate of glucose oxidation has been recognized (Randle et al., 1963; Jansson, 1980). The underlying mechanism, however, has not yet been completely clarified. Several hypotheses have been proposed. Jansson (1980) suggests that FFAs entering the muscle cell by diffusion, a concentration-dependent process, influence glucose oxidation by inhibiting two enzyms, Pyruvate Dehydrogenase (PDH) and Phosphofructokinase (PFK). PDH is inhibited by acetyl-CoA from the breakdown of FFA, PFK by citrate formed from acetyl-CoA in the first step of the citric acid cycle. The rise in concentration of these metabolites resulting from the increased breakdown of FFA thus leads to an enhanced inhibition of the degradation of glucose.
KeywordsPlasma Insulin Blood Glucose Concentration Respiratory Quotient Plasma Insulin Level Free Fatty Acid Level
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