Leptin tagged posts

Microscope photo of adipose tissue. Credit: jxfzsy/iStock/Getty Images Plus

Discovered more than 2 decades ago, the hormone leptin has been widely hailed as the key regulator of leanness. Yet, the pivotal experiments that probe the function of this protein and unravel the precise mechanism of its action as a guardian against obesity are largely missing. Flier, the HMS George Higginson Professor of Physiology and Medicine, and Maratos-Flier, HMS professor of medicine at Beth Israel Deaconess Medical Center, have made significant contributions to the understanding of the metabolism of obesity and starvation in general, and of leptin in particular.

The commentary highlights what the authors say is a startling lack of experimental evidence detailing the biologic roles of leptin in metabolism, ...

NPGL apparently aims to maintain body mass at a constant, come feast or famine.

Study explains why food looks even better when dieting. Up until now, scientists knew that leptin – a hormone released by fatty tissue, reduces appetite, while ghrelin – a hormone released by stomach tissue makes us want to eat more. These hormones, in turn, activate a host of neurons in the brain’s hypothalamus – the body’s energy control center. The discovery of NPGL by Professor Kazuyoshi Ukena of Hiroshima University shows that hunger and energy consumption mechanisms are even more complex than we realized – and that NPGL plays a central role in what were thought to be well-understood processes.

Professor Ukena first discovered NPGL in chickens after noticing that growing birds grew larger irrespective of d...

Pharmacological and genetic ablation of NG2-glia, but not microglia, leads to obesity •NG2-glial ablation causes LepR processes in the median eminence to degenerate •Arcuate nucleus LepR neurons lose responsiveness to leptin after NG2-glia ablation •X-irradiation aimed at the median eminence is sufficient for weight gain induction

Discovery opens door to development of new drugs to control weight gain and obesity. 4 years ago, Kokoeva and her team set out to explore which brain cells might play a role in the process of leptin sensing and weight gain. The answer, it turns out, lies in the median eminence, a brain structure at the base of the hypothalamus.

The McGill team has now discovered that without NG2-glia cells in place in the median eminence, the leptin receptors in the brain n...

A breakthrough study shows that fat tissue is innervated and that direct stimulation of neurons in fat is sufficient to induce fat breakdown. These results set up the stage for developing novel anti-obesity therapies. Fat tissue constitutes 20 – 25% of human body weight being an energy store in the form of triglycerides. 20 yrs ago Jeffrey Friedman and colleagues identified the hormone leptin, which is produced by fat cells in amounts that are proportional to the amount of fat, and informs the brain about how much fat is available in the body. Leptin functions as an “adipostat” neuro-endocrine signal that preserves body’s fat mass in a relatively narrow range of variation...