CARNITINE IN THE STREPTOZOTOCIN-DIABETIC RAT

Rats made moderately diabetic by streptozotocin (decreased growth without decreased body mass, blood glucose, 588-840 mg/dl) and nondiabetic rats were either fed a purified diet with no measurable carnitine (diet 1), the same diet supplemented with carnitine (44.5 nmol/g food, diet 2), or a closed formula, nonpurified diet (3.3 nmol/g food, diet 3). Levels of total carnitine (free + acyl) were lower (P < 0.05) in plasma, heart, soleus, extensor digitorum longus and kidney of rats fed diet 1 compared to those fed diet 2. Liver carnitine in diabetic animals was 2.6- to 4.4-fold higher than in nondiabetic animals with urinary carnitine of rats fed diet 1 being four times greater in diabetic than in nondiabetic rats. Other changes in tissue total carnitine were less pronounced. Compared to diabetic rats, insulin-treated diabetes had lower urinary excetion of carnitine and blood glucose levels (P < 0.05), and tissue carnitine approximating nondiabetic levels. Significant catabolism of carnitine was not found. Apparent carnitine biosynthesis (diet 1) showed no difference between nondiabetic and diabetics (31.5 .+-. 1.6 and 31.2 .+-. 2.2 nmol/g of body weight per day, respectively) suggesting elevated liver levels resulted from redistribution.