Endotoxin and cytokines induce expression of leptin, the ob gene product, in hamsters.

Abstract

The expression of leptin, the ob gene product, is increased in adipose tissue in response to feeding and energy repletion, while leptin expression decreases during fasting. Infusion of leptin decreases food intake. Because adipose tissue gene expression is regulated by cytokines induced during infection and because infection is associated with anorexia, we tested whether induction of leptin might occur during the host response to infection. Administration of endotoxin (LPS), a model for gram negative infections, induces profound anorexia and weight loss in hamsters. In fasted animals, LPS increased the expression of leptin mRNA in adipose tissue to levels similar to fed control animals. There is a strong inverse correlation between mRNA levels of leptin and subsequent food intake. TNF and IL-1, mediators of the host response to LPS, also induced anorexia and increased levels of leptin mRNA in adipose tissue. As assessed by immunoprecipitation and Western blotting, circulating leptin protein is regulated by LPS and cytokines in parallel to regulation of adipose tissue leptin mRNA. Induction of leptin during the host response to infection may contribute to the anorexia of infection. (J. Clin. Invest. 1996. 97:2152-2157.)

Leptin levels in the differential diagnosis between benign and malignant ascites

“…However, in an animal study with chronic ethanol consumption rats, it has been shown that serum concentrations of tumor necrosis factor were increased and leptin was induced in the liver and peripheral adipose tissues by TNFα [25] . In addition, experimental and animal studies have shown that TNFα is one of the major leptin producer and regulators in anorexia and inflammation [26][27][28] . It has also been suggested that leptin mediates anorexia in chronic inflammatory states [29] .…”

The link between obesity and prostate cancer: the leptin pathway and therapeutic perspectives

“…Tumor and host produced proinflammatory cytokines (IL-6, IL-1, TNFa) upregulate the OB gene in adipose tissue, 74 while leptin induces IL-6 and IGF-I production. This self-perpetuating loop allows tumor growth, involving leptin and other adipocytic molecules, contributing for tumor progression to advanced disease (Figure 3).…”

Association of genetic variants of ghrelin, leptin and UCP2 with malnutrition inflammation syndrome and survival in end-stage renal disease patients

“…It has been implied that TNF-a is related to cachexia (Tracey et al 1988). A dose-dependent increase in leptin levels was detected on endotoxin or cytokines like IL-1 or TNF-a administration in experimental animals (Grunfeld et al 1996). This suggests that weight loss and anorexia in chronic wasting diseases might be linked with leptin.…”