Leptin activates AMP-activated protein kinase in hepatic cells via a JAK2-dependent pathway.

AMP-activated protein kinase (AMPK) plays a key role in the regulation of energy homeostasis within the individual cell. Recent reports have suggested that leptin, an adipocyte-secreted hormone, phosphorylates AMPK in skeletal muscle directly. However, little is known about the interaction between leptin signaling and AMPK activation.

Identification of the promoter region required for human adiponectin gene transcription: Association with CCAAT/enhancer binding protein-beta and tumor necrosis factor-alpha.

Adiponectin, an adipose tissue-specific plasma protein, is involved in insulin sensitizing and has anti-atherosclerotic properties. Plasma levels of adiponectin are decreased in obese individuals and patients with type 2 diabetes with insulin resistance. Tumor necrosis factor-alpha (TNF-alpha) decreases the expression of adiponectin in adipocytes.

Stromal cell-derived factor-1 chemokine gene variant in patients with type 1 diabetes and autoimmune thyroid disease.

Type 1 diabetes is a heterogenous autoimmune disease and is frequently associated with other organ-specific autoimmune diseases, including autoimmune thyroid disease (AITD). Type 1 diabetic patients with AITD are known to have clinical and immunological features distinct from patients without AITD. This study investigated whether stromal cell-derived factor (SDF)-1 gene polymorphism is associated with susceptibility to type 1 diabetes and AITD.

Enhanced production of leptin in gastric fundic mucosa with Helicobacter pylori infection.

Aim: To determine the concentrations of leptin in plasma and gastric fundic mucosa in humans, with reference to Helicobacter pylori (H pylori) infection, and their association with gastric mucosal levels of interleukin (IL)-1beta, IL-6 and IL-8.

Methods: Plasma leptin concentrations were determined in 135 outpatients with non-ulcer dyspepsia, consisting of 95 H pylori-infected and 40 uninfected subjects, and 13 patients before and after cure of the infection with anti-H pylori regimen. Using biopsy samples that were endoscopically obtained from the middle corpus along the greater curvature, gastric leptin contents were measured by radioimmunoassay and the mucosal concentrations of IL-1beta, IL-6 and IL-8 were measured by enzyme linked immunosorbent assay.

Rapid inhibition of leptin signaling by glucocorticoids in vitro and in vivo.

Elevated secretion of glucocorticoids (GCs) or hypersensitivity to GCs has a permissive effect on the development of obesity and leads to abnormalities of body fat distribution. Recent studies demonstrated GCs act as antagonists of leptin in rodents. However, little is known about the interaction between GCs and leptin signaling.

Association between IL-18 gene promoter polymorphisms and CTLA-4 gene 49A/G polymorphism in Japanese patients with type 1 diabetes.

Interleukin-18 (IL-18) is a potent proinflammatory cytokine which is strongly associated with the development of diabetes in NOD mice. To test the putative involvement of IL-18 gene polymorphism in predisposition to human type 1 diabetes, the SNPs at position -607 (C/A) and -137 (G/C) in the promoter region of IL-18 gene were analyzed by sequence-specific PCR in 116 patients with type 1 diabetes and 114 normal controls. A linkage disequilibrium found only three of the four possible haplotypes defined by these SNPs.

Epitope analysis of GAD65 autoantibodies in Japanese patients with autoimmune diabetes.

Type 1 diabetes is an organ-specific autoimmune disease characterized by T cell-mediated destruction of pancreatic beta cells. In Japanese population, the incidence of type 1 diabetes in children is very low compared to European countries. However, there are more patients with type 1 diabetes in adults, including latent autoimmune diabetes in adults (LADA).

Association of interleukin-18 gene promoter polymorphisms in type 1 diabetes and autoimmune thyroid disease.

Type 1 diabetes is a heterogeneous autoimmune disease and is often associated with other organ-specific autoimmune diseases, including autoimmune thyroid disease (AITD). IL-18 is a potent proinflammatory cytokine capable of inducing IFN-gamma production that is associated with the development of type 1 diabetes and AITD. The gene for IL-18 is located near Idd2 and has been reported to be associated with a susceptibility to type 1 diabetes.

Interleukin-10 gene promoter region polymorphisms in patients with type 1 diabetes and autoimmune thyroid disease.

Type 1 diabetes is a heterogeneous autoimmune disease and is frequently associated with other organ-specific autoimmune diseases, including autoimmune thyroid disease (AITD). Type 1 diabetic patients with AITD are known to show distinct clinical and immunological features from patients without AITD. This study investigated whether interleukin-10 (IL-10) gene promoter region polymorphisms are associated with susceptibility to type 1 diabetes and AITD.

Intracerebroventricular administration of insulin and glucose inhibits the anorectic action of leptin in rats.

Obese individuals with glucose intolerance present with high serum levels of glucose, insulin, and leptin. These substances are potent inhibitors of feeding in the brain. Obese subjects still present with over-feeding despite elevation of the above factors.

Stromal-cell derived factor-1 chemokine gene variant is associated with type 1 diabetes age at onset in Japanese population.

Stromal-cell derived factor-1 (SDF-1) is a powerful chemokine that upregulates T-cell migration and activation. The gene for SDF-1 is located near type 1 diabetes susceptibility locus IDDM10, suggesting a contribution by SDF-1 to the induction of diabetes. Recently the role of SDF-1 gene polymorphism in the clinical presentation of type 1 diabetes in French population has been reported.

Insulin attenuates leptin-induced STAT3 tyrosine-phosphorylation in a hepatoma cell line.

Leptin, the 16 kDa protein product of the ob gene, is secreted by adipocytes. The long form leptin receptor (ObRb) is expressed at high levels in the hypothalamus, and regulates appetite and energy expenditure. The fact that serum concentration of leptin is correlated with body mass index (BMI) suggests reduced sensitivity to leptin.

Vanadate enhances leptin-induced activation of JAK/STAT pathway in CHO cells.

Leptin, the product of the ob gene, is an adipocyte-derived hormone that plays a key role in the control of food intake and energy expenditure. Leptin acts through receptors that belong to a member of the class I cytokine receptor family. It has been demonstrated that the SH2 domain-containing tyrosine phosphatase 2 (SHP-2) negatively regulates STAT3-mediated transcriptional activation through long form leptin receptor (OBRb).

Ethanol inhibits leptin-induced STAT3 activation in Huh7 cells.

Leptin, an adipocyte-derived hormone, regulates food intake and energy expenditure in the hypothalamus via its receptor, member of the class I cytokine receptor family. Leptin resistance has been observed in rodents and in humans. However, the mechanisms could not be explained in most cases of human obesity, except for rare cases with mutations in the leptin receptor.

Genetic association between interleukin-10 gene promoter region polymorphisms and type 1 diabetes age-at-onset.

This study investigated whether interleukin-10 (IL-10) gene promoter region polymorphisms are associated with susceptibility to or clinical presentation of type 1 diabetes. The frequency of -1082G/A, -819C/T, and -592C/A polymorphisms was analyzed in 128 Japanese patients with type 1 diabetes and in 107 healthy control subjects in a case-controlled study. The allelic and haplotypic frequencies of the IL-10 gene promoter region polymorphisms were similar in patients with type 1 diabetes and in control subjects.

[An increase in serum phenytoin concentration by changes of dosage form: case reports and its mechanism].

Phenytoin (PHT) exhibits nonlinear pharmacokinetics in the therapeutic range. Therefore a slight increase in dose may lead to considerable elevation of the serum PHT level. Although its bioavailability is dependent on the formulation, bioequivalence is considered to be preserved between the three major formulations, of tablet, 97% fine granules, and 10% powder.

Distinct IA-2 autoantibody epitope recognition between childhood-onset and adult-onset type 1 diabetes.

Different autoimmune mechanisms may be involved in childhood- and adult-onset type 1 diabetes. Our aim was to explore the differences in IA-2 autoantibody epitope recognition between childhood- and adult-onset type 1 diabetes. Therefore, in vitro synthesized radiolabeled IA-2ic (amino acid 601-979), IA-2JM (amino acid 557-629), and IA-2PTP (amino acid 630-979) were used to analyze the IA-2 autoantibody epitope specificities in 93 patients with new-onset type 1 diabetes.