Taurine fluxes in insulin dependent diabetes mellitus and rehydration in streptozotocin treated rats

Abstract

The effect of streptozotocin induced diabetes mellitus and rehydration on brain taurine and brain water content was studied in 4 groups of rats. Two groups of rats with diabetes mellitus were used. In one group, taurine and brain water content were determined following induction of diabetes for one week. In the second group, diabetes was induced for one week but before sacrifice, 15% of body weight of normal saline was introduced into the peritoneum, half at tune 0, half 30 minutes later with sacrifice 60 minutes after the first infusion. In two groups of animals (controls), the brain taurine and water content were estimated in normal conditions and after hydration, in exactly the same way as diabetic rats. Brain taurine content was greater in diabetic rats than non-diabetic rats and there was no decrease in brain taurine content within the first hour following rehydration of the diabetic rats. Brain water content was greater in rehydrated diabetic rats than in non-rehydrated diabetic rats but there was no significant change in the brain water content after hydration of non diabetic rats. This suggested that the rapid change in water content of rehydrated diabetic rats was not accompanied by an equally rapid alteration in brain taurine content. This is consistent with the hypothesis that taurine flux could be a major factor in the aetiology of diabetic cerebral oedema. It also allows the development of possible therapeutic options which may increase outward taurine flux from brain cells. Taurine flux is increased by increasing extracellular sodium concentration or decreasing potassium concentration. Phospholemman channels may also influence taurine flux. These may have implications for the optimal method of clinical rehydration undertaken in diabetic ketoacidosis.