Insulin resistance in the level of blood sugar can result in the classic hyperglycemic triad of polyphagia (increased appetite), polydipsia (increased thirst), and polyuria (increased urination). Avoiding carbohydrates and sugars, a no-carbohydrate diet or fasting can reverse insulin resistance. When the body produces insulin under conditions of insulin resistance, the cells are resistant to the insulin and are unable to use it as effectively, leading to high blood sugar. Beta cells in the pancreas subsequently increase their production of insulin, further contributing to a high blood insulin level. This often remains undetected and can contribute to the development of type 2 diabetes,
Insulin suggests that it has been conserved across much of animal evolutionary history. The C-peptide of proinsulin (discussed later), however, differs much more among species; it is also a hormone, but a secondary one. The primary structure of bovine insulin was first determined by Frederick Sanger in 1951. After that, this polypeptide was synthesized independently by several groups. The 3-dimensional structure of insulin was determined by X-ray crystallography in Dorothy Hodgkin's laboratory in 1969 (PDB file 1ins). Insulin is produced and stored in the body as a hexamer (a unit of six insulin molecules), while the active form is the monomer.