The goal of the study extension is to see whether the incretin hormone GIP increases insulin secretion in individuals with CF and normal glucose tolerance compared to individuals without CF and normal glucose tolerance.

The purpose of the study is to evaluate blood sugar levels and beta-cell function in adolescents and adult with KATP hyperinsulinism whom did not undergo pancreatectomy.

The Congenital Hyperinsulinism Center at the Children's Hospital of Philadelphia is working on a research study to better understand how people with hyperinsulinism may have different blood sugar responses to certain tests (like fasting or drinking a high-protein shake) when compared to people without hyperinsulinism.