Until now, cholesterol circulation in the blood was thought to be “exclusively regulated through dietary absorption or synthesis and secretion by the liver,” according to Matthias H. Tschöp, an endocrinologist at the University of Cincinnati College of Medicine. But Tschöp and his colleagues have found evidence that cholesterol circulation is also controlled by the brain (Nat. Neurosci., DOI: 10.1038/nn.2569). The researchers studied the activity of ghrelin, a hormone produced primarily by the gut. Production of the hormone increases before meals and stimulates appetite and feeding through inhibition of the melanocortin 4 receptor in the hypothalamus region of the brain. Working with rats and mice, the team determined that boosting ghrelin levels reduces the liver’s uptake and metabolism of HDL—the “good” cholesterol—and thereby increases the amount of HDL circulating in the blood. Although they caution that rodent and human cholesterol differ, the researchers believe their findings could offer a new route for pharmacological control of cholesterol levels.