A Yale researcher has discovered that the lipid NAPE—N-acylphosphatidylethanolamine, excreted by the small intestine, travels to the brain,concentrates in the hypothalamus, and suppresses hunger in rats and mice. Rats wearing an IV vest that delivers NAPE for days ate less than controls and lost weight.

Howard Hughes Medical Institute investigator Gerald Shulman at Yale School of Medicine led the research team, which reported its findings in the November 26, 2008, issue of the journal Cell. Shulman's research group is well known for its work on understanding how insulin resistance develops and leads to diabetes. In the course of that research, his team developed a sensitive system to identify and measure lipids in tissue samples. After seeing the power of that system in his diabetes research, Shulman was eager to see if it might also be applied to understanding obesity.

Note that a low fat and high carbo diet might set you up for more hunger (this is obviously not an original thought). Only fat causes NAPE release and appetite suppression in rats.

They found only low levels of NAPE in the blood of rats that had fasted for 12 hours. The level of NAPE shot up 40 to 50 percent in animals that had dined on high-fat chow. Furthermore, NAPE didn't increase in rodents that ate only protein or carbohydrate, suggesting that NAPE levels reflect the amount of fat eaten in a meal.

The researchers found that when they injected synthetic NAPE into the abdominal cavity or blood, the rodents' appetites diminished substantially. The more NAPE they received, the less food they ate. "It's really quite effective," Shulman says. "At the highest doses, it keeps the animals from eating for up to 12 hours." At a low dose—comparable to the spike in NAPE that occurs naturally after a meal—the rodents still ate 25 percent less than controls. They even acted full, going into "siesta mode" as if they had just eaten, Shulman says, noting that additional tests confirmed that the animals were only lethargic, not ill or incapacitated.

The scientists are going to study NAPE in primates and humans with the hope of finding evidence to justify clinical trials.

If periodic injections or some other method of delivery could work for humans then NAPE might serve as an effective compound for weight loss. Though I'm concerned how the clinical trials would get funding. NAPE occurs naturally in the body. Can a drug company get a patent on it for weight loss so that an incentive would exist to spend the hundreds of millions of dollars needed to go through the clinical trials and drug application process?

Human appetite, like many other basic human desires, is going to become very manipulable with pharmaceuticals. Which basic desire do you most want to increase or decrease?