Effects of intrabrachial arterial infusion of pyruvate on forearm tissue metabolism: Interrelationships between pyruvate, lactate, and alanine

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Abstract

Postabsorptive release of alanine from forearm skeletal muscle is large relative to other amino acids, suggesting new synthesis by transamination of pyruvate. This hypothesis was tested and the pathway quantified in six subjects, each given two 30 min intrabrachial arterial pyruvate infusions. The first (12 μmoles/min) supplied approximately that amount of pyruvate produced endogenously by glycolysis in resting muscle. The second (36 μmoles/min) approximated endogenous pyruvate production by glycolysis during moderate exercise. Changes in balance across forearm tissues of pyruvate, glucose, lactate, and amino acids were measured. The time-course of pyruvate equilibration across fore-arm muscles was detailed in three additional subjects.

Authors

Thomas Pozefsky, Robert G. Tancredi