The Dean lab seeks to understand how nutritional and other environmental factors affect pancreatic islet cell function and proliferation. Islet alpha cells secrete glucagon in response to hypoglycemia leading to increased glucose output by liver, but persons with diabetes often have hyperglucagonemia further contributing to hyperglycemia. Very little is known about signals regulating alpha cells. We have used a mouse model with interrupted glucagon signaling that displays alpha cell hyperplasia and hyperglucagonemia to identify circulating factors that stimulate alpha cell proliferation. We described that these circulating factors are amino acids defining a novel hepatic-pancreatic islet alpha cell axis that is conserved across vertebrate species. The Dean lab is current interested in 1) defining the mechanism of how amino acids are sensed by alpha cells to stimulate proliferation and glucagon secretion and 2) investigating the role of amino acids on alpha cell dysfunction in diabetes.
