There is a clearly documented link between diabetic complications and lipid peroxidation. Hyperglycemia causes a reduction in levels of protective endogenous antioxidants and increases generation of free radicals. The present study was carried out to compare the protective effects of melatonin and vitamin E against streptozocin (STZ)-induced diabetes in rats. Melatonin was administered s.c. (100 microg/kg) whereas vitamin E was given i.p. (100 mg/kg) after induction of diabetes with STZ (60 mg/kg). Plasma total cholesterol, triglyceride and low density lipoprotein (LDL) levels were increased in STZ group while both melatonin and vitamin E injection caused a significant decrease in the levels of all these parameters. The lipid lowering effect of melatonin was greater than that of vitamin E. Melatonin caused a significant decrease in brain, liver and kidney tissue malondialdehyde (MDA) levels which were increased because of STZ-induced diabetes. Vitamin E also reduced elevated MDA concentrations in diabetic rat tissues, but the effect of melatonin was more potent than that of vitamin E. Furthermore, treatment of diabetic rats with melatonin increased brain and kidney glutathione peroxidase (GSH-Px) activity to the levels below that of control rats. Vitamin E was found to be less effective on GSH-Px activity levels in brain and kidney than melatonin whereas it was more potent than melatonin in liver. In summary, melatonin prevents many diabetic complications by reducing oxidative stress and protects organisms from oxidative damage and dyslipidemia. Considering the much lower molar concentration of melatonin compared with vitamin E, melatonin seems to be a more potent antioxidant, especially in the brain and kidney.

The purpose of this study was to examine platelet aggregation during Ramadan fasting. A group of 20 healthy non-smoking male volunteers were studied, whose mean age was [21 (SD 2.4) years range 19-24]. The average fast was about 15 h. Venous blood samples were taken on 4 different days; 1 day before Ramadan (day 0), then on the 1st, 14th and 28th day of Ramadan. On each of these 4 days, blood samples were taken at 4 p.m. (1 h before the evening meal). Body mass index and platelet count did not change during fasting. Bleeding and coagulation time had increased significantly by the end of Ramadan fasting (P < 0.05, P < 0.005 respectively), but these changes remained within physiological limits. Ramadan fasting induced a reduction in platelet sensitivity to adenosine 5'-diphosphate (ADP) and collagen on days 14 (P < 0.05) and 28 (P < 0.05, P < 0.005 respectively). However, adrenaline-induced platelet aggregation decreased only on day 28 (P < 0.05). This study indicated that Ramadan fasting led to a decrease in the platelet responses of different aggregating agents (ADP, adrenaline and collagen) in vitro. It also led to an increase in bleeding and coagulation time.

The effects of castration and eııogenous testosterone hormone on the levels of serum glucose, cholesterol and creatinine in Akkaraman ram lambs. Suınınary