Abstract
A previous report from our laboratory (Collier et al 1993) showed that the elongated tubules of mitochondria in the cytoplasm of cultured chicken embryo fibroblasts collpased to irregularly shaped structures surrounding the nuclear membrane after a 1 h heat shock treatment. The normal mitochondiral morphology reappeared upon removal of then thermal stress. We have now determined that several changes occured in mitochondrial-related metabolites under these same heat shock and recovery conditions. Among these were significant decreases in the levels of fumarate and malate and increases in the amounts of aspartate and glutamate. In contrast, other intermediates of the tri-carboxylic acid cycle were unaltered as were levels of ATP and phosphocreatine. The changes observed might result from heat shock-induced changes in enzyme activities of the mitochondria or from alterations in the membrane-embedded specialized carrier proteins that transport metabolites between cytosol and mitochondria, from a disorganization of the electron-transport system normally coupled to oxidative metabolism. The rapid recovery, however, suggested that these changes were transient and readily reversible.
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