The distribution of total, free, short-chain acyl and long-chain acyl carnitine in ocular tissues of the camel (Camelus dromedarius).

Abstract

Carnitine (CA) plays an important role in the metabolism of fatty acids. Its presence is considerable in tissues that utilize fatty acids as an important source of energy, such as the heart and the skeletal muscle. The presence of free, short-chain acyl and long-chain acyl carnitine was shown for the first time in various tissues of the camel eye. The ratio of acyl carnitine (AC) to free carnitine (FC) was high in aqueous humor, indicating a predominance of AC, while it was low in vitreous humor, indicating a higher concentration of FC. The highest concentration of total carnitine (TC) was observed in the retina, followed by the cornea, while the lowest was found in lens nucleus. Among various forms, FC concentration was the highest in the cornea while it was the lowest in the lens cortex. In the cornea and retina, the proportion of short-chain acylcarnitines (SC) was two-fold when compared to long-chain acylcarnitines (LC), while in the lens it was the same. The ratio of AC to FC in the retina was high, indicating a predominance of AC, while in lens it was low, indicating a higher concentration of FC. In contrast, L-CA in the cornea was present equally between the free and the esterified forms. The quantitative differences in the distribution of L-CA in various tissues of the camel eye reflect that it may be involved in providing a source of readily available energy.