Long-term effectiveness of oral vanadyl sulphate in streptozotocin-diabetic rats

• Published in: Diabetologia 1993-03, Vol.36 (3), p.218-224
• Main Authors: CAM, M. C, PEDERSON, R. A, BROWNSEY, R. W, MCNEILL, J. H
• Format: Article
• Language: English
• Subjects: Adipose Tissue - drug effects; Adipose Tissue - metabolism; Administration, Oral; Animals; Biological and medical sciences; Blood Glucose - metabolism; Body Weight - drug effects; Diabetes Mellitus, Experimental - drug therapy; Diabetes Mellitus, Experimental - metabolism; Diabetes Mellitus, Experimental - pathology; Drinking Behavior - drug effects; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Feeding Behavior - drug effects; Gastric Inhibitory Polypeptide - pharmacology; Glucose - pharmacology; Glucose Tolerance Test; Glycerol - metabolism; Hypoglycemic Agents - administration & dosage; Hypoglycemic Agents - therapeutic use; Hypoglycemic Agents - toxicity; In Vitro Techniques; Insulin - metabolism; Insulin Secretion; Islets of Langerhans - drug effects; Islets of Langerhans - metabolism; Kidney - drug effects; Kidney - pathology; Liver - drug effects; Liver - pathology; Male; Medical sciences; Rats; Rats, Wistar; Vanadium - administration & dosage; Vanadium - therapeutic use; Vanadium - toxicity; Vanadium Compounds
• ISSN: 0012-186X; 1432-0428
• DOI: 10.1007/BF00399953

Recent studies have demonstrated the insulin-like effects of oral vanadyl sulphate in the streptozotocin-diabetic rat, including the amelioration of hyperglycaemia and the prevention of diabetes-related cardiac and adipose tissue dysfunction. However, the possibility that vanadyl treatment, routinely initiated at 3 days after the induction of diabetes, had prevented the full cytotoxic destruction of the beta cell, and thus accounted for the apparent anti-diabetic properties of vanadyl was questioned. Hence in the present study, we examined the effectiveness of vanadyl sulphate as a glucose-lowering and anti-diabetic agent when administration was delayed from the time of induction of diabetes. Male Wistar rats were injected with a single intravenous dose of streptozotocin (55 mg/kg). Vanadyl sulphate was administered in the drinking water at a concentration of 0.75 mg/ml from 3, 10 and 17 days after the streptozotocin injection and treatment was then maintained for 5 months. Vanadyl intake was accompanied by lowered serum levels of triglyceride and cholesterol with no associated enhancement in circulating insulin. Vanadyl-treated diabetic animals showed improved glucose tolerance while insulin release in vivo was still markedly lower than in non-diabetic rats. Adipose tissue function, as expressed by basal and epinephrine-stimulated lipolysis in isolated adipose tissue, was also normalized in vanadyl-treated diabetic animals. These responses were all observed whether vanadyl treatment was initiated 3, 10 or 17 days after induction of diabetes. Finally, prolonged treatment with vanadyl sulphate (in this case up to 5 months) did not cause any apparent hepatic toxicity as assessed histologically. Diabetes-induced morphological changes in the kidney were also prevented by vanadyl treatment.