The effect of prolonged hyperglycemia on metabolic alterations in the subtotally pancreatectomized rat

A delayed onset of diabetes is characteristic of subtotally pancreatectomized patients in whom persistent hyperglycemia per se is documented to lead to the development of insulin resistance. This study was conducted to elucidate the metabolic alterations seen during transition of the acute to chronic phase after subtotal pancreatectomy (SP). Eight male Sprague-Dawley rats were studied 2 weeks after surgery in the acute phase, and the other eight at 4 weeks in the chronic phase. Phosphoenolpyruvate carboxykinase (PEPck) for gluconeogenesis and the malic enzyme for de novo fatty acid synthesis in the liver showed a reciprocal change, the former activity being increased, while the latter was suppressed. Both alterations were more pronounced in the chronic phase. In the acute phase, lipoprotein lipase (LPL) for triglyceride clearance decreased in the adipose tissue, while that in the cardiac and skeletal muscle became significantly elevated. The latter elevations were decreased in the chronic phase. Sustained hyperglycemia in the SP rats not only increased the changes in PEPck and malic enzyme activities but reversed the tissue-specific muscle LPL elevations. These changes might help to explain the wasting condition seen in surgically induced diabetic patients.