Insulin Secretion and Action

Abstract

Because glucose is the primary energy source of most cells in the body, control of constant circulating glucose levels is of utmost importance. Too little serum glucose (hypoglycemia) suppresses central nervous system functions and prolonged hypoglycemia leads to death. Too much serum glucose (hyperglycemia) as seen in diabetes mellitus, results in grave consequences such as kidney, nerve, eye, muscle, and immune system damage. The body has an elaborate system to control circulating glucose levels in a narrow range (72–126 mg/dL) to prevent untoward fluctuations. For populations in Western societies, the predominant problem in glucose metabolism is diabetes mellitus although other derangements are significant but not often encountered. Of all the humoral and neuronal regulatory mechanisms for glucose metabolism, insulin is the hormone that lowers serum glucose whereas most other mechanisms function to increase serum glucose.