Effects of a hydroalcoholic extract of walnut male flowers on diabetic rats

Diabetes is a metabolic disorder resulting from defects in insulin secretion and function. Walnut is used in traditional medicine to treat diabetes. In this study we evaluated the anti-diabetic effects of the hydroalcoholic extract of walnut male flowers in streptozocin diabetic rats and its probable side effects on the liver. Eighty adult male Wistar rats were randomly selected and divided into 4 subgroups including a control [N=8] with no intervention, witness group receiving normal saline and another 3 groups of rats each receiving either 2, 4, or 6 g/kg of the extract per day for 15 days. Diabetic groups of rats each treated with the above doses of the extract for the aforementioned period of time, and a group of 8 diabetic rats without any further treatment. Eight rats were also used to determine the LD50 of streptozotocin. Diabetes was induced in rats by injection of 60 mg/kg of streptozotocin. At the end of the experimental period, blood was taken from the experimental and control groups and the serum levels of insulin, glucose and liver enzymes [ALT, AST, ALP] were measured. Results showed that the hydro-alcoholic extract of walnut male flowers increased the levels of insulin, decreased blood glucose, AST and ALP enzymes in the treated diabetic groups compared to the non-treated group [p<0.05]. The anti-diabetic effects of the extract were not dose dependent. The effectiveness of the hydro-alcoholic extract of walnut male flowers in diabetic rats through prevention of liver damage and reduction of blood glucose

Pre- and post-treatment of streptozocin administered rats with melatonin: effects on some hepatic enzymes of carbohydrate metabolism

Melatonin, found in high concentrations in the pineal gland, organs within the digestive system and in some plants and fungi, acts as an antioxidant which decreases reactive oxygen species in streptozocin-induced diabetic rats, raises insulin secretion by the pancreatic [3-cells and increases the number of insulin receptors on hepatocyte membranes. The protective and therapeutic effects of melatonin feeding in streptozocin-induced diabetic rats were studied. Streptozocin administered rats were gavaged with melatonin, pre- and post-treatment, at a level of 5 mg/kg body weight daily for a period of 15 days. Levels of plasma glucose, cholesterol, triacylglycerol, oral glucose tolerance test, and some hepatic enzymes of carbohydrate metabolism including insulin inducible glucokinase, hexokinase and glucose 6-P dehydrogenase were measured using standard methods and compared with the values in normoglycemic and diabetic control groups. Both pre- and post-treatment of the Streptozocin administered rats with melatonin normalized plasma glucose, cholesterol, and triacylglycerol, improved oral glucose tolerance test and increased hepatic glucokinase, hexokinase and glucose 6-P dehydrogenase specific activities to the levels seen in normal rats. Melatonin pre-treatment prevents the injurious effects of Streptozocin in rats. In Streptozocin induced diabetic animals, post-treatment with this antioxidant normalizes both blood and liver constituents which were ameliorated by Streptozocin

Hepatic arylsulfatases A and B activities in streptozocin - induced diabetic rats

Reduction of sulfated glycosaminoglycans [GAG] in the liver and kidney of streptozocin-induced diabetic rats has been attributed to lowered synthesis and perhaps higher degradation of such compounds in these organs. To measure hepatic lysosomal arylsulfatases A and B, [the enzymes responsible for the removal of sulfate groups from GAG], in starved and streptozocin-induced diabetic rats. Diabetes was induced by streptozocin injection [40 mg per kg body weight] through the caudal vein in rats. After two weeks, the livers were removed and homogenized. Activities of arylsulfatases A and B were measured and compared with those of the liver homogenates from healthy and starved rats. The activity of liver arylsulfatase A in starved diabetic rats increased 2.15 fold as compared with normal starved animals, while that of fed diabetic rats was 3.16 fold higher than their respective control group. Increases of 1.70 and 1.94 fold in specific activities of arylsulfatase B was noticeable in the livers of diabetic animals under fed and starved conditions, respectively. It appears that increased hydrolysis of sulfated GAG by liver lysosomal arylsulfatases A and B in streptozocin-induced diabetic rats may be among the contributing factors in the reduction of such sulfated compounds in this tissue