Insulin Increases Facilitated Diffusion of Glucose The rate of glucose transport, as well as transport of some other monosaccharides, is greatly
increased by insulin. When large amounts of insulin are secreted by the pancreas, the rate of glucose
transport into most cells increases to 10 or more timesthe rate of transport when no insulin is secreted.
Conversely, the amounts of glucose that can diffuse to the insides of mostcells of the body in the
absence of insulin, with the exception of liver and brain cells, are far too little to supply the amount of
glucose normally required for energy metabolism.In effect, the rate of carbohydrate utilization by most
cells is controlled by the rate of insulin secretion from the pancreas.The functions of insulin and its
control of carbohydrate metabolism are discussed in detail in Chapter 78.
