Insulin (medication) release of insulin from the pancreas. The increased insulin level causes glucose absorption and storage in cells, reduces glycogen to glucose conversion, reducing blood glucose levels, and so reducing insulin release. The result is that the blood glucose level rises somewhat after eating, and within an hour or so, returns to the normal 'fasting' level. Even the best diabetic treatment with synthetic human insulin or even insulin analogs, however administered, falls far short of normal glucose control in the non-diabetic. Complicating matters is that the composition of the food eaten (see "glycemic index") affects intestinal absorption rates. Glucose from some
Glucose glucose themselves from certain precursors as the need arises. Nerve cells, cells of the renal medulla and erythrocytes depend on glucose for their energy production.<ref name="Löffler/Petrides 195">Peter C. Heinrich: "Löffler/Petrides Biochemie und Pathobiochemie." Springer-Verlag, 2014, , p. 195. (german)</ref> In adult humans, there are about 18 g of glucose, of which about 4 g are present in the blood. Approximately 180 to 220 g of glucose are produced in the liver of an adult in 24 hours. Many of the long-term complications of diabetes (e.g., blindness, kidney failure, and peripheral neuropathy) are probably due to the glycation of proteins or