Scientists have added a new twist to the body of evidence suggesting human obesity is due in part to genetic factors.
While studying hormone receptors in laboratory mice, researchers at Mayo Clinic's campus in Florida and Washington University School of Medicine identified a new molecular player responsible for the regulation of appetite and metabolism.
The authors report that mice engineered not to express the lipoprotein receptor LRP1, in the brain's hypothalamus, began to eat uncontrollably, growing obese as well as lethargic. They found that LRP1, a major transporter of lipids and proteins into brain cells, is a "co-receptor" with the leptin receptor - meaning that both the leptin and LRP1 receptors need to work together to transmit leptin signals.
Leptin decides whether fat should be stored or used, resulting in lethargy or energy. When working properly, the hormone, which is made when body cells take in fat from food, travels to the brain to tamp down appetite...