International Journal of Endocrinology and Metabolism
Volume:9 Issue: 1, Jan2011

Cardiovascular disorders are a major cause of morbidity and mortality in diabetic patients. Increased vascular permeability is a hallmark of diabetic vasculopathy, and the administration of natural products with antioxidant activity could restore vascular function. In this study, the effect of chronic treatment with sesamin on vascular permeability in rats with streptozotocin (STZ)-induced diabetes was investigated. Male diabetic rats received sesamin at a dose of either 10 or 20 mg/kg for 7 weeks, beginning 1 week after diabetes induction. Vascular permeability was estimated by measuring Evans blue dye extravasation. Oxidative stress markers, including malondialdehyde (MDA) and superoxide dismutase (SOD) activity, were also measured in aortic tissue. Extravasation of Evans blue dye increased significantly in the diabetic group compared to that in the control group (p < 0.05), and treatment with sesamin significantly and dose-dependently decreased this extravasation (p < 0.05). Diabetic rats also had elevated malondialdehyde (MDA) and reduced superoxide dismutase (SOD) activity (p < 0.005–0.001), and chronic treatment with sesamin (20 mg/kg) significantly reversed the elevated MDA content (p < 0.05) and reduced SOD activity (p < 0.05). Chronic treatment of diabetic rats with sesamin could dose-dependently improve aortic permeability, partly through the attenuation of oxidative stress in aortic tissue.

Obesity is associated with several chronic conditions such as atherosclerosis and hypertension. All of these are risk factors that contribute to metabolic syndrome, which in turn can lead to cardiovascular disease and type 2 diabetes. In this study, we aimed to show the relationship between insulin resistance and serum levels of adiponectin, an anti-inflammatory adipokine, in obese men with type 2 diabetes.Patients and Serum concentrations of adiponectin, insulin, and glucose were measured in 48 obese men (BMI > 29) with type 2 diabetes, aged 37 to 53 years and having a body weight of 80 to 100 kg. Insulin resistance index values were calculated using measurements of fasting glucose and insulin levels. Using Pearson’s correlation test, the relationship of serum adiponectin concentration with insulin resistance, serum glucose, and insulin levels, was determined. The results showed a significant inverse relationship between adiponectin concentration and insulin resistance in type 2 diabetic patients (p = 0.000, r = -0.59). In addition, a significant relationship was observed between fasting glucose and adiponectin levels (p = 0.005). The relationship between insulin and adiponectin levels was not significant (p = 0.196). Our findings indicate that the concentration of adiponectin, an anti-inflammatory and antidiabetic marker, is a precise insulin resistance predictor in obese patients with type 2 diabetes.

Insulin-like growth factor-1 (IGF-1) and IGF-binding protein 3 (IGFBP-3) are used widely for evaluating growth hormone deficiency (GHD). We evaluated the effect of recombinant human growth hormone treatment on serum IGF-1 concentrations in Indian children with GHD over a period of 24 months.Patients and Patients who presented with short stature were evaluated. The enrolled subjects exhibited a height standard deviation score (SDS) of less than -3 and/or a height velocity SDS of less than -2 over a 12-month period, and they displayed GH concentrations of less than 10 ng/ml in 2 provocative tests. Patients received a detailed physical examination that included auxology, pubertal staging, and biochemical assays to measure IGF-1 concentration. All patients received GH at a dose of 0.3 mg/kg/week in 7 divided doses subcutaneously daily at night. Patients with multiple pituitary hormone deficiencies received additional substitution therapy. Twenty-five prepubescent children (male:female = 14:11) at a mean age of 8.6 ± 2.9 years were enrolled. The height SDS at baseline, 1 year, and 2 years was -5.38 ± 1.4, -4.10 ± 1.4, and -3.6 ± 1.3, respectively (P < 0.005), whereas the IGF-1 SDS at baseline, 1 year, and 2 years was -3.40 ± 0.8, -1.74 ± 1.2 and, -1.54 ± 1.7, respectively (P > 0.1). No significant difference in height change SDS was detected between children with an IGF-1 SDS in the normal range and children with an IGF-1 SDS of less than -2 at 2 years. Bone age advancement, the occurrence of puberty, and levels of fasting glucose and HbA1C did not change during therapy. Our study on Indian children indicates that changes in serum IGF-1 SDS concentrations may not be a reliable marker for responsiveness to GH therapy.

Previous studies have suggested reduced fat metabolism in older subjects. However, corrections for their reduced maximal oxygen consumption and the effects of training and substrate availability have not been fully examined. Fat metabolism (FM) in older subjects (n = 14, 75 ± 7 yrs), and the effects of exercise training were compared with FM in younger subjects (n = 16, 22 ± 3 yrs). All subjects completed a maximal exercise test and a sustained submaximal run at 70% of their maximal capacity. The respiratory exchange ratio (RER) and blood substrate levels were determined. Older subjects were re-tested after training. Young subjects had higher oxygen consumption (VO2) peak (36.3 ± 6.7 vs. 23.7 ± 6.2 ml/kg/min) and lower slope of RER vs. VO2 than older subjects. However, the slope of the RER vs. VO2 relationship was not different between younger and older subjects, after correction for their VO2 peaks. Younger subjects had longer sustained exercise times (45.5 ± 17.6 min) than the elderly (30.2 ± 14.0 min), pre-training. Post-training, there was a significant increase in VO2 peak (25%) in older subjects (P = 0.001) and submaximal exercise time (30.2 ± 14.0 vs. 58.3 ± 27.3min, P = 0.020). Respiratory exchange ratio was reduced during both exercises after training (0.90 ± 0.03 vs. 1.00 ± 0.03, P = 0.04). The RER of older subjects was not different from that of younger subjects, after correction for the VO2 peak. The VO2 peak, sustained exercise time, and RER decreased after training in older subjects, indicating increased fat metabolism.

Galanin is an orexigenic agent and has been demonstrated to be a putative regulator of gonadotropin secretion. It is well known that this orexigenic peptide probably plays a vital role in the regulation of reproduction; however, the underlying mechanisms have not been fully elucidated. The goal of this study was to determine the role of galanin in the regulation of gonadotropins in goats, which were subjected to either high or low energy diets. Adult female Saanen goats were randomly divided into 2 groups. Animals in the two groups were fed either a 100% or a 150% energy content diet, respectively, for a month. On the first day of the experiment, all animals received an intravenous injection of 1 µg galanin/kg body weight. On the second day, each animal was administered 2 µg galanin/kg body weight. Blood samples were withdrawn by jugular venipuncture at 30-minute intervals, 3.5 h before and 3.5 h after galanin injection. In order to determine the concentration of LH and FSH, plasma was isolated and subjected to radioimmunoassay in order to determine the concentrations of relevant gonadotropin hormones. The intravenous administration of 1 µg galanin/kg body weight to goats who were subjected to a high-energy feed significantly reduced circulating LH and FSH levels. It contrast, this dose had no effect on goats subjected to the lower energy diet. The injection of galanin at a dose of 2 µg/kg body weight had no influence on mean plasma concentrations of gonadotropins in goats fed either of the two diets. The results indicate that galanin is not a principal hypophyseal regulator in the secretion of gonadotropins in Saanan goats. It may be inferred that in the same animal model galanin has a gonadotropin-reducing effect when its in vivo concentration increases.