Acute effects of estradiol and of diethylstilbestrol: Pro- or antioxidant potential?

This study was aimed to examine the effects of a single high dose of natural and synthetic estrogens on the antioxidant defense enzymes in liver and blood. Female Wistar albino rats, four to six months old, were divided into three groups, and received either i.p. injections of diethylstilbestrol (DES; 150 mg kg(-1) b.w.) or s.c. injections of estradiol (E-2; 25 mg kg(-1) b.w.), and the third group (control) was injected the solvent. Animals were killed under light ether anesthesia three hours after injection. Cu-Zn superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat) enzyme activities and fluorometric malondialdehyde (MDA) determination were performed in liver tissue homogenates and in blood. Acute estradiol injection caused a significant increase in both MDA levels and GPx activity in liver tissue when compared to the controls, (p < 0.05 and p < 0.02; respectively). Changes in both enzyme activities and MDA concentration were unremarkable following acute DES injection. In blood, only Cu-Zn SOD activity was significantly altered in blood following E-2 injection. Although the significance of alteration in GPx activity remains unclear, it is most likely related to enhanced generation of lipoperoxides. A significant increase in MDA concentrations in liver tissue is indicative of pro-oxidative damage rather than an antioxidant action by E-2

Advanced oxidation protein products in obese women: its relation to insulin resistance and resistin

Obesity is a major risk factor for insulin resistance and type 2 diabetes mellitus (TZDM). Resistin, an adipocyte-secreted hormone, is thought to take a part in the development of insulin resistance and T2DM. The aim of this study was to characterise the changes in circulating levels of resistin and proinflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 in diabetic and prediabetic obese patients and to explore their relationship to insulin resistance. Attempts were also made to see whether resistin levels are related to the degree of oxidative stress, as determined by the measurement of advanced oxidation protein products (AOPPs). The study groups consisted of obese diabetic (BMI: 30-42 kg/m(2), n=28) and prediabetic (BMI: 29-41 kg/m(2), n=23) women. Fourteen healthy women, with BMI in the range 21.5-25.5 kg/m2, were taken as controls. Serum levels of TNF-alpha, IL-6, resistin, glucose, insulin and AOPPs were measured. Insulin resistance was calculated by the homeostasis model assessment (HOMA-IR). Diabetic and prediabetic obese patients had increases in serum resistin and TNF-a levels (P < 0.01 and P < 0.001, respectively). IL-6 levels in diabetic patients were significantly higher than in prediabetics (P < 0.05). AOPP levels were also significantly higher in diabetics than prediabetics and controls (P < 0.05 and P < 0.001, respectively); and positively correlated with blood glucose. Insulin was significantly associated with circulating resistin and TNF-a. The development of insulin resistance may contribute to the elevation of circulating resistin or vice versa. Determination of AOPPs may be helpful for monitoring the impaired glucose metabolism in obesity