Studies on vitamin B12 status in blood and tissue of alloxan diabetic animals.

Although the role of vitamin B12 in relation to diabetes mellitus is not fully understood, there are evidences to substantiate that this micronutrient plays an im portant role directly or indirectly in carbohydrate metabolism (1). It has been shown to relieve hyperglycemia and glycosuria (2) under various experimental con ditions. A decrease in the activities of glycolytic enzymes and some other SH enzymes in vitamin B12 deficiency was also reported by Biswas and Johnson (3). The vitamin B12 levels of serum and urine in diabetic patients with or without retinopathy, has been a subject of conjecture as controversial reports have been obtained by different workers on the subject (4, 5). According to some, diabetics with retinopathy excrete significantly more of the vitamin than non-diabetics, while diabetics without retinopathy excrete considerably less amounts of the vitamin than the nondiabetics (4). On the other hand, Bookman et al. (5) found a lack of cor relation with vitamin Bi2 excretion in diabetics (with or without retinopathy) and normal subjects. Serum levels of vitamin B12 in diabetics with retinopathy was found to be much higher than those without retinopathy (6). However, others failed to find significant difference in serum vitamin B12 levels between diabetics and normal persons (7). However, a decreased blood vitamin B12 in diabetes mellitus was evidenced by some other workers (8). In view of the above observations it was thought worthwhile to investigate into the true picture of vitamin B12 status in diabetes. In the earlier reports it has been shown that the vitamin B12 levels of the serum and liver decrease with higher ketone bodies in the animal system (9,10). In the present investigation, therefore, vitamin B12 levels of serum and liver were estimated in alloxan diabetic animals under different levels of ketone bodies.