Insulin-potentiating action of antioxidants in experimental diabetes mellitus
The objective of this work was to study effects of alpha-lipoic acid (α-LA), 3-oxypyridine and succinic acid derivatives (emo­xipine, reamberine, and mexidole) on the metabolic status, conditioned reflex learning, and motivated behaviour in rats with alloxan-induced diabetes receiving basal insulin therapy. The data obtained were compared with effects of the above antioxidants (AO) on insulin sensitivity and results of glucose tolerance test in intact animals. It was shown that administration of AO during two weeks corrected disturbances of carbohydrate and lipid metabolism, normalized the behaviour and learning in terms of the conditioned reflex in diabetic rats. These effects depended on the influence of antioxidative compounds on insulin sensitivity and tolerance of glucose loading. The best correction of diabetic manifestations was achieved using course doses of a-LA that maximally enhanced insulin sensitivity and of mexidole that markedly improved glucose tolerance. It is concluded that significant elevation of blood lipoperoxide levels in rats with alloxan-induced diabetes following administration of AO agents for 14 days gives no evidence of the direct relationship between their efficiency and antioxidative action.