Effect of lactation on insulin sensitivity of glucose metabolism in rat adipocytes

AbstractDuring lactation glucose metabolism in paraovarian adipocytes is characterized by a 40 and 80% decrease of glucose incorporation into CO2 and fatty acids in the presence of insulin. In contrast with the stimulation by insulin of glucose incorporation into lactate, glycerol remains unchanged. As a result, insulin sensitivity of total glucose metabolism (oxidation and lipid synthesis) is not altered in adipocytes from lactating rats

Serum Visfatin and Fetuin-A Levels and Glycemic Control in Patients with Obese Type 2 Diabetes Mellitus

BackgroundVisfatin is an adipokine produced by visceral adipose tissue and has insulin-mimicking effects. Fetuin-A is a hepatic secretory protein that binds the insulin receptor and inhibits insulin action both in vivo and in vitro. The authors of the present study aimed to investigate the levels of serum visfatin and fetuin-A and their correlation with hemoglobin A1c (HbA1c) and urine albumin levels in patients with type 2 diabetes mellitus (T2DM).MethodsA total of 40 obese patients with T2DM (11 males and 29 females; age, 54.47±10.83 years and 23 obese nondiabetic controls (8 males and 15 females; age, 53.04±11.33 years) were included in the study. Age, sex, and body mass index were similar in the 2 groups. Serum visfatin and fetuin-A levels were measured by enzyme-linked immunosorbent assay. HbA1c and urine albumin levels were measured by high performance liquid chromatography and nephelometric method, respectively.ResultsSerum levels of visfatin in patients with T2DM (4.03±2.44 ng/mL) were similar to the control group (3.65±3.02 ng/mL). Serum fetuin-A levels were significantly lower in patients with T2DM than the controls (298.75±78.86 and 430.73±94.46 µg/mL, respectively). HbA1c levels were significantly higher in the T2DM group compared with controls (7.33±1.32 and 5.44±0.84%, respectively). Correlations between visfatin, fetuin-A and HbA1c levels were not observed.ConclusionThe present study suggests fetuin-A may play a role in the pathogenesis of T2DM

Adipose tissue transcriptomic signature highlights the pathological relevance of extracellular matrix in human obesity

Analysis of the transcriptomic signature of white adipose tissue in obese human subjects revealed increased interstitial fibrosis and an infiltration of inflammatory cells into the tissue

Low intense physical exercise in normobaric hypoxia leads to more weight loss in obese people than low intense physical exercise in normobaric sham hypoxia

Training in mild to moderate hypoxia (14–17% O2 in breathing air) and extended resting in moderate hypoxia (9–13% O2) have been shown to have effects in animals and humans on lipid and glucose metabolism, appetite loss, and, in part, on body weight. The causality for these effects is not yet known in detail, and the available data in humans from high-altitude and low-pressure chamber studies are scarce. New technical developments by German companies in the production of artificial climates with normobaric hypoxic conditions in larger rooms at reasonable energy costs allow now to perform hypoxia weight loss studies in obese humans with stable experimental conditions and protocols with a sham hypoxia control. Thirty-two obese people were recruited for a mild intense training study in normobaric hypoxia (15 vol.% O2) and normoxia/sham hypoxia (20.1 vol.% O2). Twenty of these [mean age 47.6 years, mean body mass index (BMI) 33.1, 16 m, 4 f) were willing to follow up on an 8-week, three times per week, 90-min low intense physical exercise in their individual fat burning mode, which has been determined by an exercise testing with spiro-ergometry upfront. The subjects were evenly randomized into a hypoxia and sham hypoxia group. The difference of the two groups in weight loss and changes in HBa1C values were analyzed before and after the training period. No nutritional diet was applied. Subjects in the hypoxia group in mean lost significantly more weight than in the sham hypoxia group (Δ1.14 kg vs Δ0.03 kg; p = 0.026). This resulted in a tendency to reduce the BMI more in the hypoxia group (p = 0.326). In the mean, there was no HbA1C exceeding normal values (mean 5.67 and 5.47%), and the HbA1C stayed basically unchanged after the 8-week training. Mild physical exercise three times per week for 90 min in normobaric hypoxia for 8 weeks led to significantly greater weight loss in obese persons than the exercise in sham hypoxia in this, to our knowledge, first sham hypoxia controlled study

Thiazolidinediones repress ob gene expression in rodents via activation of peroxisome proliferator-activated receptor gamma

The ob gene product, leptin, is a signaling factor regulating body weight and energy balance. ob gene expression in rodents is increased in obesity and is regulated by feeding patterns and hormones, such as insulin and glucocorticoids. In humans with gross obesity, ob mRNA levels are higher, but other modulators of human ob expression are unknown. In view of the importance of peroxisome proliferator-activated receptor gamma (PPARgamma) in adipocyte differentiation, we analyzed whether ob gene expression is subject to regulation by factors activating PPARs. Treatment of rats with the PPARalpha activator fenofibrate did not change adipose tissue and body weight and had no significant effect on ob mRNA levels. However, administration of the thiazolidinedione BRL49653, a PPARgamma ligand, increased food intake and adipose tissue weight while reducing ob mRNA levels in rats in a dose-dependent manner. The inhibitory action of the thiazolidinedione BRL49653 on ob mRNA levels was also observed in vitro. Thiazolidinediones reduced the expression of the human ob promoter in primary adipocytes, however, in undifferentiated 3T3-L1 preadipocytes lacking endogenous PPARgamma, cotransfection of PPARgamma was required to observe the decrease. In conclusion, these data suggest that PPARgamma activators reduce ob mRNA levels through an effect of PPARgamma on the ob promoter

Adiponectin in Women with Polycystic Ovary Syndrome

BACKGROUND: Though adiponectin has been associated with insulin resistance and cardiovascular risk factors, the relationship between adiponectin and polycystic ovary syndrome (PCOS) remains controversial. The aim of this study was to compare adiponectin level in women with PCOS and without PCOS, and to investigate the relationship between adiponectin level and metabolic variables including insulin resistance. METHODS: 60 women with PCOS were enrolled along with a control group of 80 healthy women, matched for age and body mass index (BMI). We measured hormonal and metabolic parameters, as well as the plasma adiponectin concentration of each participant. We estimated the insulin sensitivity according to the quantitative insulin sensitivity check index (QUICKI). RESULTS: The PCOS group displayed significantly lower level of adiponectin (P < 0.001) after adjustment for age, BMI, mean blood pressure, fasting glucose, fasting insulin, and several metabolic parameters. Adiponectin levels were positively correlated with QUICKI in the PCOS group (P < 0.001) and the control group (P = 0.03). Following step-wise multiple regression analysis, however, adiponectin level was positively correlated with QUICKI in the control group only (P = 0.03). In addition, adiponectin level was found to be independently associated with HDL-cholesterol level (P < 0.001) and BMI (P = 0.02) in the PCOS group and independently associated with HDL-cholesterol (P = 0.02) in the control group. CONCLUSION: We report decreased adiponectin level in PCOS patients in relation to controls independently of insulin resistance or other metabolic factors. And adiponectin is associated with both lipid metabolism and obesity, which, in turn, is related to insulin resistance in PCOS. Further studies are needed to clarify the mechanism of adiponectin in PCOS.ope