Effects of Streptozotocin, Fructose and Sucrose-induced Insulin Resistance on Plasma and Urinary Electrolytes in Male Sprague-Dawley Rats
Background: Several groups in recent times have related the pathogenesis of renal haemodynamic changes in diabetes and most of the experimental diabetic conditions studied so far were carried out using streptozotocin injection only.
Objective: The aim of the present study was to examine the effects of streptozotocin, fructose and sucrose induced insulin resistance on plasma and urinary electrolytes. Closely related to this aim, was the view to suggest which profoundly potentiate insulin resistance more between fructose and sucrose.
Methods: Thirty-six male Sprague-Dawley rats were randomly divided into 6 groups Group 1 > control group. Group 2 > served as streptozotocin group, rendered diabetic by a single dose IP injection of Streptozotocin 45 mg/kg in 0.1 M freshly dissolved in Na+ citrate buffer pH 4.5. Hyperglycaemia confirmed after 48 hours. Groups 3 and 4 > served as 25% fructose and 50% fructose groups respectively; fed on a diet containing 25% and 50% fructose (W/W) for 12 weeks. Groups 5 and 6 > served as 25% sucrose and 50% sucrose groups respectively; fed on a diet containing 25% and 50% sucrose (W/W) for 12 weeks. Hyperglycaemia confirmed at the 12th week.
Results: Plasma and urinary sodium and potassium were significantly higher (P < 0.05) in the 25% and 50% sucrose groups compared to the other groups. Plasma and urinary chloride was significantly higher (P < 0.05) in the 25% and 50% fructose groups compared to the other groups. Plasma creatinine and urea was significantly higher (P < 0.05) in the streptozotocin, 25% and 50% Sucrose groups compared to all the other groups. Urinary creatinine and urea was significantly higher (P < 0.05) in the streptozotocin, and 25% Fructose groups compared to all the other groups.
Conclusion: The elevated levels of plasma and urinary electrolytes are presumptive markers of diabetes associated lesions in the kidneys of rats. Fructose potentiated insulin resistance effect more than sucrose though sucrose might have more effect on renal sodium handling.
Keywords: Streptozotocin, Fructose, Sucrose, Insulin resistance, Electrolytes