Ca2+-transport in skeletal muscle sarcoplasmic reticulum of the chronically diabetic rat.

Ca2+-transport in fast skeletal muscle sarcoplasmic reticulum preparations was studied in experimentally-induced diabetic rats 90 days after treatment. A significant decrease in ATP-dependent oxalate facilitated Ca2+-uptake was observed in these animals at all free Ca2+ concentrations tested (0.1-2.0 microM). A concomitant elevation in the levels of both free carnitine and long-chain acylcarnitine was also found. These observations paralleled results obtained in diabetic rat heart sarcoplasmic reticulum preparations and suggest a generalized pathophysiological mechanism affecting muscle tissue function in the diabetic animal.