Two distinct conditions: diabetes insipidus and diabetes mellitus. Diabetes insipidus is a metabolic disorder characterised by extreme thirst, excessive consumption of liquids and urination, due to failure of secretion of the antidiuretic hormone. haemochromatosis is known as bronze diabetes.
Diabetes mellitus is a metabolic disorder involving impaired metabolism of glucose due either to failure of secretion of the hormone insulin (Type I, insulin-dependent diabetes) or impaired responses of tissues to insulin (Type II, non-insulindependent diabetes). If untreated, the blood concentration of glucose rises to abnormally high levels (hyperglycaemia) after a meal and glucose is excreted in the urine (glucosuria). Prolonged hyperglycaemia may damage nerves, blood vessels and kidneys, and lead to development of cataracts, so effective control of blood glucose levels is important.
Type I diabetes develops in childhood (sometimes called juvenile- onset diabetes) and is due to failure to secrete insulin as a result of progressive auto-immune destruction of pancreatic β- islet cells.Treatment is by injection of insulin, either purified from beef or pig pancreas, now usually, biosynthetic human insulin, together with restriction of the intake of sugars.
Type II diabetes generally arises in middle age (maturityonset diabetes) and is due to insulin resistance of tissues; secretion of insulin by the pancreas is higher than normal in the early stages of the disease. It can sometimes be treated by restricting the consumption of sugars and reducing weight, or by the use of oral drugs which stimulate insulin secretion and/or enhance the insulin responsiveness of tissues (sulphonylureas and biguanides).