Type-2's will have enough insulin being produced but the insulin receptors on the cells cannot accept the insulin. At the same time insulin is produced, C-Peptides are also produced. Therefore in type-2's you will find plenty of C-Peps but the insulin comes to a closed door and drugs have to be taken to open the doors, (the keys). Type-1's don't produce insulin and C-Peps will therefore be low, indicating type-1 diabetes. See below.
The amount of C-peptide in the blood can indicate the presence or absence of disease. For example, abnormally low amounts of C-peptide in the blood suggest the insulin production is too low (or absent) because of type I, also known as juvenile or insulin-dependent diabetes. Abnormally high amounts of C-peptide warn of the possible presence of a tumor called an insulinoma that secretes insulin.
Normal levels of C-peptide may signal that all is well. However, in a person with diabetes, a normal level of C-peptide indicates the body is making plenty of insulin but the body is just not responding properly to it. This is the hallmark of (adult insulin-resistant diabetes). C-peptide, therefore, plays a crucial diagnostic role as regards insulin.
Insulin is a hormone that regulates the body's use of glucose. Muscle cells and other types of cells need glucose to generate energy. The body manufactures glucose from food, mainly carbohydrates. It is the job of insulin to deliver glucose to an energy-consuming body site. There it knocks on the front door and places the glucose into the hands of the occupant. The occupant then uses the glucose to help its master -- the body -- walk, run, throw, lift, and carry out other activities. Football players, mountain climbers and lumberjacks all thrive on the energy glucose provides. Insulin also prevents glucose overload in the bloodstream by lowering the level of blood glucose as necessary. Insulin is released by cells in the pancreas called the islets of Langerhans. JB.