There's a new entry in the field of weight-controlling hormones, a finding of potential importance to the millions of Americans trying to lose weight without giving up their zest for eating.
The Stanford University researchers who discovered it have named it obestatin. It acts to suppress appetite, and its commercial possibilities are noted by sponsorship of the research by the pharmaceutical company Johnson & Johnson.
Obestatin joins leptin, melanocortin and ghrelin, hormones identified in the last few years as acting on appetite and weight. So far, work with those molecules has not produced the hoped-for cure for obesity.
The obestatin discovery comes with a couple of twists. One is that it's produced by the same gene that produces ghrelin, which acts to suppress appetite. Another is that major credit for the discovery is given to Charles Darwin's theory of evolution.
The principles of evolution led to identification of obestatin, said Aaron Hsueh, a professor of obstetrics and gynecology at Stanford, in whose laboratory the work was done. He also credited the information gathered by the Human Genome Project, which produced a complete human gene map.
Hsueh and his colleges used human genome data to study small-peptide hormones, which are active throughout the body. Specifically, they looked at the receptors for those hormones -- the cellular molecules to which the hormones are attached when they go into action. There are about 300 such receptors, of which 100 had no known hormone partner.
The search for missing hormones was narrowed by focusing on receptors that have been around for hundreds of millions of years and are found in many species. One of those receptors is for ghrelin. Further studies showed that ghrelin actually had another protein tacked on to it -- obestatin.
When the researchers injected obestatin into rats, "to our surprise, we found that treatment with it suppresses food intake," Hsueh said. And so, he added, "it could have potential as an appetite-suppressing drug, by injection. Or it might be possible to deliver by nasal spray. It also allows us to screen for new drugs that might suppress appetite."
The study findings appear in the Nov. 11 issue of the journal Science.
But Matthias Tschop, associate professor of psychiatry at the University of Cincinnati, and co-author of an editorial in the journal on obestatin, is sounding a note of caution.
"The effect of obestatin on body weight seems to be relatively limited," Tschop said. "Also, it might cause some sort of illness or nausea that causes a decrease in food intake."
The effect of obsestatin was discovered in research with rodents, Tschop noted. "The most obvious question is, does obestatin work in obese animals?" he said.
And the business of weight regulation is complicated, Tschop added. "There are many other players involved," he said. "And obestatin may have many other functions. For example, it could regulate physical activity."
But with all those caveats taken into consideration, the discovery of obestatin is "a step in the right direction," Tschop said.
Arteries' 'Repair Crews' Key to Heart Disease
It's the job of specialized bone marrow cells to repair damage to the lining of arteries, and the failure of these cells to keep up with that deterioration may be key to atherosclerosis (hardening of the arteries), researchers report.
Bacterium, Gene Play Roles in Elderly Vision Loss
The diseased eye tissue of some patients with "wet" age-related macular degeneration (AMD) contains a bacterium called Chlamydia pneumoniae, which can cause chronic inflammation and has been linked to heart disease, researchers report.
New Pain Control System Approved
The U.S. Food and Drug Administration has approved the Medtronic Personal Therapy Manager (PTM), allowing people with chronic pain to use Medtronic's SynchroMed II drug pump to manually deliver supplemental doses of pain medication, the company said.
Warning Issued for Birth-Control Patch
The Food and Drug Administration warned users of the popular Ortho Evra birth control patch that they are being exposed to more hormones, and are therefore at higher risk of blood clots and other serious side effects, than previously disclosed.
China Reports New Bird-Flu Outbreaks
China on Friday reported its fourth bird flu outbreak in chickens in the same province in two weeks, while Vietnam -— which has suffered two-thirds of Asia's human deaths from the virus -— ordered its military and police to help fight the disease.
Kuwait Flamingo Has Deadly Bird-Flu Strain
The deadly strain of bird flu that has devastated poultry and killed more than 60 people in Asia has been detected in a bird in Kuwait, the first known outbreak of the virus in the Gulf region, an agricultural official said Friday.
Food Fact: Sap to it!
Guess how many gallons of raw sap it takes to make 1 gallon of pure maple syrup? When the sap starts running, Vermont sugarmakers start stoking the fire under the evaporators -- there are 40 gallons of raw sap per gallon that reaches your breakfast table. The all-natural sweetener is loaded with calories -- 50 per tablespoon -- and has no significant nutritive value. But it's so flavorful a little will go a long way. Maple sugar is about twice as sweet as refined granulated sugar, and is produced when nearly all the sap has evaporated. Try it sprinkled on scones or biscuits or stirred into hot apple cider.
Fitness Tip of the day: Write it down.
Stuck in a rut? Reached a plateau? Break the logjam with an activity log! Keeping a fitness journal to track your routine will give you insight into your performance, let you measure your progress and help you set goals.
FAQ of the day: What is mesclun?
Mesclun is an assortment of baby lettuce leaves, usually prewashed. The mix may be expensive, but there's no waste. It's so convenient you may find yourself eating a mesclun salad with every meal.