SERUM AND URINE LEVELS OF LEVOCARNITINE FAMILY COMPONENTS IN GENETICALLY DIABETIC RATS

Serum concentration and urinary excretion of levocarnitine (L-carnitin e, CAS 541-15-1) family components were evaluated in a Wistar derived strain of genetically diabetic rats BB/BB, in comparison with normal W istar rats, and their control rats BB/WB of both sexes. BB/ BB diabeti c animals have lower serum concentration of total-L-carnitine (TC), L- carnitine (LC), acetyl-L-carnitine (ALC), and short chain L-carnitine esters (SCLCE) than both the strains of non-diabetic rats, as previous ly observed in streptozotocin diabetic rats. No or marginal variations between control and diabetic rats were detected in cumulative urinary excretion of L-carnitine family components. A strain difference was o bserved between Wistar and BB/WB non-diabetic rats, BB/WB showing high er serum concentration and lower cumulative urinary excretion of LC an d TC than Wistar animals. Renal clearance of L-carnitine components pr oved to be markedly higher in BB/BB diabetic rats, as previously shown in streptozotocin rats. The reduction of serum concentration of the c arnitines endogenous pool may explain this finding. The lack of an inc reased urinary excretion of L-carnitine components in diabetic animals despite the high increase of diuresis suggests that the saturable tub ular reabsorption of L-carnitine family components also in diabetes is the primary mechanism to preserve the homeostatic equilibria of the L -carnitine family, the variation in serum concentration being attribut able to the complex systemic metabolic alterations typical of diabetes . In agreement with previous investigations, male animals of all the s trains showed higher serum concentration and urinary excretion of L-ca rnitine components as compared to females.