It is not known whether obesity increases the risk for hepatocellular carcinoma (HCC) simply because it promotes cirrhosis, a general risk factor for HCC, or via some other mechanism that operates independently of cirrhosis. If the latter occurs, then hepatocyte hyperplasia, an early event during the neoplastic process, might begin before liver cirrhosis develops. Genetically obese, leptin-defi...

A quantitative method for circulating islet cell surface antibodies (ICSA), based on the binding of 125I-protein A to insulin-producing RINm5F cells, was used to evaluate ICSA in plasma of 4- to 40-week-old Aston obese hyperglycaemic (ob/ob) mice and normal control (+/+) mice. RINm5F cells bound 2502 +/- 1196 c.p.m. 125I-protein A per 10(5) cells (mean +/- S.D., n = 54) after incubation with +/...

The adipocyte-derived hormone leptin is an important regulator of appetite and energy expenditure and is now appreciated for its ability to control innate and adaptive immune responses. We have reported previously that the leptin-deficient ob/ob mouse exhibited increased susceptibility to the Gram-negative bacterium Klebsiella pneumoniae. In this report we assessed the impact of chronic leptin ...

Aquaporin (AQP) is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway. AQP7 and AQP9 are membrane proteins with water and glycerol channels, the latter of which is essential for triglyceride synthesis. We conjectured that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in obese leptin deficient ob/ob...

We investigated the effects of lactation on diurnal changes in serum leptin and hypothalamic expression of the leptin receptor isoforms, Ob-Ra, -Rb, -Rc, -Re and -Rf in rats. In non-lactating rats, serum leptin concentration was increased at night while hypothalamic mRNA levels of Ob-Rb, -Rc and -Re decreased; by contrast, expression of Ob-Ra and Ob-Rf was unchanged at night. There were signifi...

Leptin is an adipose tissue-secreted hormone that acts via specific receptors (Ob-R), of which six isoforms are at present recognized (from Ob-Ra to Ob-Rf). Ob-Rb is the only isoform able to activate JAK-STAT and MAPK signaling cascades. A large body of evidence suggests that leptin and its receptors are involved in prostate physiology and pathophysiology in humans, but studies on the leptin sy...

Obesity is a major health care problem and is associated with significant cardiovascular morbidity. Leptin, a neuroendocrine hormone released by adipose tissue, is important in modulating obesity by signaling satiety and increasing metabolism. Moreover, leptin receptors are expressed on vascular endothelial cells (ECs) and mediate angiogenesis. We hypothesized that leptin may also play an impor...

OBJECTIVE Direct health care costs of obesity continue to grow throughout the world and research on obesity disease models are on the rise. The ob/ob mouse is a well-characterized model of obesity and associated risk factors. Successful breeding and backcrossing onto different backgrounds are essential to create knockout models. Ob/ob mice are sterile and heterozygotes must be identified by gen...

The potent hypophagic effect of OB protein (OB) is well established, but the mechanism of this effect is largely unknown. We investigated the effects of chronic administration of a novel modified recombinant human OB (Mod-OB) with a prolonged half-life (>48 h) on ad libitum food intake, spontaneous meal patterns, and body weight in 24 adult, male Sprague-Dawley rats (body weight at study onset:...

Leptin is produced almost exclusively by adipocytes and regulates body weight at the hypothalamic level. In addition, recent studies showed that leptin plays an important role in T lymphocyte responses. To examine the role of leptin in Ag-induced arthritis, the development of joint inflammation was assessed in immunized leptin-deficient mice (ob/ob), +/?, and wild-type mice (+/+) following the ...