Insulin - decreasing hormone found in flies and humans

An insulin-regulating hormone that, until now, only had been postulated to exist has been identified by researchers at the School of Medicine. The hormone, called limostatin after the Greek goddess of starvation, Limos, tamps down circulating insulin levels during recovery from fasting or starvation. In this way, it ensures that precious nutrients remain in the blood long enough to rebuild starving tissues, rather than being rapidly squirreled away into less-accessible fat cells. The researchers first discovered limostatin in fruit flies but then quickly identified a protein with a similar function in humans. “Starvation or famine is an ancient, ever-present specter faced by all living organisms,” said Seung Kim, MD, PhD, professor of developmental biology. “The ways to deal with it metabolically are likely to be ancient and conserved. This research clearly connects the dots between flies and humans, and identifies a new potential way to regulate insulin output in humans.” In particular, members of a family with an inherited mutation in the human analog of limostatin exhibited many of the same physiological characteristics as flies genetically engineered to be unable to produce limostatin — namely, high levels of circulating insulin, low blood sugar levels and a tendency toward early onset obesity. A paper describing the research findings was published Feb. 3 in Cell Metabolism. Kim is the senior author, and graduate student Ronald Alfa is the lead author.