Leptin The Sentinel Protein
March 17, 2009
LEPTIN: THE OBESITY SENTINEL PROTEIN
Leptin is an adipocyte-derived protein hormone originally thought to function solely as a satiety signal, although it is now apparent that leptin can act both centrally and in the periphery to regulate a host of physiological processes.
Leptin is produced predominantly by fat cells, functions as a sentinel of energy balance, and has been recently identified as an important bone regulatory factor. The obese ob/ob mouse, which cannot produce leptin due to an inactivating mutation in the leptin gene has skeletal abnormalities; compared to wildtype (WT) mice, ob/ob mice have reduced bone length and reduced overall bone mass. These findings suggest leptin is required for optimal peak bone growth and quality.
This includes growth, fertility and glycemic control, as evidenced by leptin deficient ob/ob mice, as well as regulation of the hypothalamic-pituitary-adrenal (HPA) axis, bone growth, and T-cell immunity and the inflammatory response.
WHAT TELLS US TO STOP HOGGING?
The single element that rings the warning bell when we keep on hogging is the chemical called ‘leptin’. The protein Leptin is secreted by the adipose cells. Following the discovery of the vital chemical and its functions, a revolution took place in the world of medical science.
DOES LEPTIN HELP IN ANY OTHER WAY?
A latest research has proved that ‘leptin’ is connected with puberty, sterility, and obesity.
The levels of leptin in blood determine when puberty should begin. Leptin levels are more in chubby children than in athletic or thin ones. That explains the reason why the former attains puberty earlier than the latter. Studies on female mice have thrown up interesting data. With the female mice injected with leptin two processes were expedited: viz., not just puberty but also reproduction!
It has also been found that leptin content in the body is inextricably linked with puberty and obesity.
STUDIES SIGNALS FAT ACCUMULATION TO THE BRAIN
‘Leptin’ is the agent that keeps on signaling to the brain the fat amount accumulated in a person’s body. Extensive studies on mice have shown that when the leptin levels are low they are bereft of the crucial signals not to eat. As a result, they keep on hogging with the natural consequence that these genetically treated mice start becoming obese.
These mice also became sterile. But, once they were injected with leptin, they regained their fertility.
