AJP - Regulatory, Integrative and Comparative Physiology, Vol 237, Issue 3 174-R180, Copyright © 1979 by American Physiological Society
Computer simulation of metabolism in pyruvate-perfused rat heart. IV. Model behavior
M. J. Achs, M. C. Kohn and D. Garfinkel
The behavior of a computer model of energy metabolism was determined for
perfused rat hearts utilizing pyruvate as sole exogenous fuel and subjected
to a rapid increase in work load. Computer-generated metabolite profiles,
which are solutions of the differential equations for 1 min elapsed time,
closely match 12 experimental curves (involving 120 concentration
measurements) and exhibit the following properties. The computed cytosolic
pyruvate level oscillates due to large changes in the rates of the
processes that produce and consume this metabolite. Cytosolic Mg2+ seems to
act as a coordinated controller of glycolytic enzymes; its transient
increase permits a transient increase of glycolysis without an accumulation
of glucose 6-phosphate. Lactate is exported to the interstitium by a
lactate permease and then reimported and oxidized. As a result, the
malate-aspartate shuttle reverses direction, and the Krebs cycle is
"unspanned."
