That, in turn, stops them oxidising lipids and opens those cells to lipids' toxic effects.
The glycol is, in turn, covered by a membrane made of two layers of lipids (fat-like molecules).
The enzyme deficiency causes fatty materials (lipids) to collect in the spleen, liver, kidneys, and other organs.
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Leptin has several roles, but one is to encourage cells to oxidise lipids and thus destroy them.
The ability of the tissue to absorb lipids and keep the rest of the body safe thus drops.
In one with broken receptors, a mere 6% is enough to overload other tissues to the point where lipids would be toxic.
One mystery yet to be solved is why people with Syndrome X have smaller particles of low density lipids, the type of cholesterol most likely to block arteries.
More subtly, though, the two researchers have dug up evidence that an excess of lipids damages heart-muscle cells, and even destroys pancreatic cells in rodents.
For example, cholesterol and lipids are measured and abnormal levels treated.
Adiponectin, meanwhile, encourages the body's adipose tissue to absorb lipids.
To save themselves when they are threatened with being overwhelmed by lipids, cells become insulin-resistant, which stops them taking up extra glucose which would then be converted into lipids.
In a healthy mouse (one with working leptin receptors) even a diet that is 60% fat does not cause a build-up of lipids anywhere except in the adipose tissue.
And liposuction (not, admittedly, something that most doctors would recommend) would be expected to make things worse, since it would get rid of the source of the hormones that regulate lipids.
His own work involves such things as understanding the makeup and behavior of less-understood critical components of cells, like lipids and glycols, and how a cancer cell might bind with a nanoparticle.
In light of all this, they suggest that insulin resistance, like obesity, should be viewed not as a pathology but as an adaptive response by the body to an excess of circulating lipids.
Dr Unger and Dr Scherer suggest that this failure of the leptin mechanism, particularly its role in oxidising lipids, is crucial to the development of metabolic syndrome, and that it is a pathology of adipose tissue that has become overloaded.
Among them: I-Stat, owned by Abbott Laboratories (nyse: ABT - news - people ), which makes a handheld device for basic chemistry that uses so-called ion-selective membranes, and Cholestech (nasdaq: CTEC - news - people ), which has a lipids testing machine and relies on a glucometerlike optical reflection technology.
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