ROANOKE TIMES
Copyright (c) 1995, Roanoke Times
DATE: Friday, December 29, 1995 TAG: 9512290085
SECTION: NATIONAL/INTERNATIONAL PAGE: A-6 EDITION: METRO
SOURCE: The Washington Post
Only six months after scientists discovered a protein in blood that tells the body when to stop eating, a competing research team has found the molecular ``antenna'' that receives that message and passes it on to fat-burning and appetite control centers.
The discovery, achieved after a furious search through hundreds of candidate molecules, is expected to speed development of new treatments for obesity.
The newfound antennas, known as leptin receptors, are convoluted proteins that stud the outer surface of brain cells and perhaps other cells in the body. Scientists believe that when these receptors detect leptin, the body's recently discovered ``fullness signal,'' they pass a ``stop eating'' message toparts of the brain. A series of discoveries in the past few months has suggested that obesity is often caused by a defect in this receptor - or in the still unidentified relay stations to which the receptor passes its message.
Scientists said that, with the leptin receptor in hand, it should be relatively easy to identify those second- and third-tier relay stations, revealing for the first time the molecular chain of events that regulates appetite and energy metabolism. Ultimately, they hope to find drugs that act specifically on those mechanisms.
``How things will turn out in the end is difficult to predict, but I'm very optimistic,'' said Louis A. Tartaglia, the scientist at Millennium Pharmaceuticals in Cambridge, Mass., who led the search. ``The goal will be to tickle the receptor.''
Tartaglia reported the work in today's issue of the journal Cell along with Robert I. Tepper and others from Millennium and scientists from Hoffman-La Roche, the Swiss pharmaceutical company. Indicative of the intense interest in the receptor, Cell published the results only three weeks after receiving the manuscript. It typically takes several months for scientific journals to publish reports.
The work builds on research by Rockefeller University scientist Jeffrey Friedman, who last July announced the discovery of a weight-controlling protein called leptin, made by fat cells. As fat stores build up, fat cells release more leptin, suppressing appetite and adjusting metabolic rates to maintain the body's normal weight.
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