The adipose tissue-derived hormone leptin regulates body weight homeostasis by decreasing food intake and increasing energy expenditure. The weight-reducing action of leptin is thought to be mediated primarily by signal transduction through the leptin receptor (LR) in the hypothalamus. We have used immunohistochemistry to localize LR-immunoreactive (LR-IR) cells in the rat brain using an antise...

Ducroc R, Sakar Y, Fanjul C, Barber A, Bado A, Lostao MP. Luminal leptin inhibits L-glutamine transport in rat small intestine: involvement of ASCT2 and BAT1. Am J Physiol Gastrointest Liver Physiol 299: G179–G185, 2010. First published May 6, 2010; doi:10.1152/ajpgi.00048.2010.—L-glutamine is the primary metabolic fuel for enterocytes. Glutamine from the diet is transported into the absorptive...

Background: Leptin regulates appetite through the long isoform of its receptor in the hypothalamus. Although leptin regulates immune responses, it is still unknown whether a direct effect of leptin on lymphocytes is required. Aims: To clarify whether expression of leptin receptors on T lymphocytes modulates intestinal inflammation in mice. Methods: The model of colitis induced by transfer of CD...

Aging associates with an increased pro-inflammatory activity that is commonly associated with oxidative tissue damage. One pro-inflammatory molecule that facilitates oxidative stress is leptin, a hormone that regulates metabolism, endocrine and immune functions. To address whether leptin levels correlated with oxidative stress in aging, we performed cross-sectional measurements of circulating p...

Recent studies have reinforced the view that the lateral hypothalamic area (LHA) regulates food intake and body weight. We identified leptin-sensitive neurons in the arcuate nucleus of the hypothalamus (Arc) that innervate the LHA using retrograde tracing with leptin administration. We found that retrogradely labeled cells in the Arc contained neuropeptide Y (NPY) mRNA or proopiomelanocortin (P...

A very low dose of leptin (50 ng) was microinjected into the ventro-medial hypothalamus (VMH) of each rat daily once for three days. Food intake and body weight were measured after leptin injections. Microinjection of leptin into the VMH reduced food intake by 33.3 % significantly (P<0.01) during three days of leptin injection compared to the control. Body weight was measured after 24 h, 48 h a...

Leptin directly increases the rate of exogenous glucose and fatty acids oxidation in isolated adipocytes. However, the effects of leptin on fatty acid metabolism in white adipose tIssue have not been examined in detail. Here, we report that in adipocytes incubated for 6 h in the presence of leptin (10 ng/ml), the insulin-stimulated de novo fatty acid synthesis was inhibited by 36% (P<0.05), whi...

We have previously determined that exogenous leptin prevents the inhibition of pulsatile luteinizing hormone (LH) release in the fasting rodent. The present study tested the hypothesis that the mechanism by which leptin facilitates high LH secretion is through an attenuation of the stress response produced by a deficit in energy. Because hypogonadotropism is associated with activation of the hy...