Carnitine concentration in skeletal muscle tissue from patients with diabetes mellitus.

L-Carnitine concentration was determined in vastus lateralis and abdominal rectus muscle tissue from 15 patients with diabetes mellitus and 66 controls. Nine of the diabetics were treated with diet and hypoglycemic drugs only and six with insulin. The carnitine concentration was determined enzymatically with labeled [I-14C] acetyl-coenzyme-A as a substrate and given per weight of non-collagen protein. The concentration in muscle tissue did not differ significantly between patients and controls. Patients with insulin-treated diabetes had the same concentration of carnitine in muscle tissue as those treated with hypoglycemic drugs. The drastic decreases in carnitine muscle concentration and in carnitine body pool seen in alloxan-diabetic rats are not observed in skeletal muscle of diabetic humans.