where can glucose be found in the body
Glycogen Approximately 4Â grams of glucose are present in the blood of humans at all times;[2] in fasted individuals, blood glucose is maintained constant at this level at the expense of glycogen stores in the liver and skeletal muscle.[2] Glycogen stores in skeletal muscle serve as a form of energy storage for the muscle itself;[2] however, the breakdown of muscle glycogen impedes muscle glucose uptake, thereby increasing the amount of blood glucose available for use in other tissues.[2] Liver glycogen stores serve as a store of glucose for use throughout the body, particularly the central nervous system.[2] The human brain consumes approximately 60% of blood glucose in fasted, sedentary individuals.[2]
Insulin Insulin (from the Latin, insula meaning island) is a peptide hormone produced by beta cells of the pancreatic islets, and it is considered to be the main anabolic hormone of the body.[5] It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of, especially, glucose from the blood into fat, liver and skeletal muscle cells.[6] In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both.[6] Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood.[7] Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells. Low insulin levels in the blood have the opposite effect by promoting widespread catabolism.