New technique for the isolation of functional rat pancreatic mitochondria and its application to models of pancreatic injury.

The role of mitochondria in the initiation or promotion of pancreatic pathologic conditions has not been clearly delineated. In this context, it has recently been suggested that abnormal mitochondrial function may account for the fat accumulation observed in pancreatic acinar cells in alcoholism. To study these issues, we developed a method for the isolation of functional mitochondria from the rat pancreas. The resultant mitochondrial pellet possessed oligomycin-insensitive Mg2+-adenosine triphosphatase (ATPase) activity, and coupled respiration could be demonstrated in the presence of EDTA only after Mg2+ had been excluded from the incubation medium. Albumin was also a requirement for the demonstration of coupled respiration in vitro. When this new technique was applied to a rat model of alcohol-induced pancreatic steatosis, no mitochondrial dysfunction was demonstrated, suggesting that some other mechanism is responsible for fat accumulation in pancreatic acinar cells after long-term ethanol consumption. In contrast, DL-ethionine administration to rats produced partial or total uncoupling of mitochondrial respiration in the absence of morphologic evidence of mitochondrial injury.