HOMA IR C - Peptide Model

Glucose - Fasting Blood Test is done to measure the levels of glucose in blood during period of fasting.

Glucose is the main source of energy for body. Carbohydrates consumed in the diet are broken down in the body to glucose, which is absorbed by the intestines and transported by the blood to various organs. The cells of these organs utilize the glucose to produce energy when required, and the excess is stored either as glycogen in the liver for short-term storage or in fat tissues as triglycerides for long-term storage. The uptake, utilization, and storage of glucose after it is absorbed in the intestines is facilitated by the hormone- insulin which is secreted by the pancreas. Insulin influences the transport of glucose to the organs like heart, brain, working muscles, etc. It also directs storage of excess glucose. The action of insulin reduces sugar levels in the blood.

After a meal, sugar levels increase in blood and insulin is secreted in response to reduce sugar levels until it becomes normal. If glucose levels fall too low in blood, another pancreatic hormone called glucagon is released, which directs the liver to convert stored glycogen into glucose and releases it into the blood. The insulin and glucagon hormones create a feedback mechanism to keep blood glucose levels within the normal range. Imbalance in their activity causes an excess or shortage of blood sugar.

Glucose - Fasting blood Test helps to determine if the body is able to utilize or store glucose efficiently. High levels of sugar in blood indicates diabetes or resistance to insulin. Type 1 Diabetes is caused when insulin is not produced or produced in very little quantity. Type 2 Diabetes is caused when insulin produced is not utilized effectively by the body. In both these cases, blood sugar level rises, while cells are deprived of nutrition.

C-peptide is a short chain of amino acids released into the blood as a by-product of insulin production. This test measures the amount of C-peptide in blood and helps evaluate the production of insulin made by the body (endogenous). This helps in differentiating endogenous insulin from the insulin that is not produced by the body but is taken in as diabetic medication (exogenous). This is possible because the insulin that is taken in as diabetic medications does not generate C-peptide.

Beta cells of the pancreas produce proinsulin which is a biologically inactive molecule. This molecule splits apart to form one molecule of C-peptide and one molecule of insulin. The uptake, utilization, and storage of glucose after it is absorbed in the intestines is facilitated by the hormone called insulin. When insulin is released from the beta cells into the blood in response to increased levels of glucose, equal amounts of C-peptides are also released. Since C-peptide is produced at the same rate as insulin, it is useful as a marker of insulin production.