Deficiency of which hormone in the body causes diabetes mellitus?
Insulin
Diabetes mellitus is caused due to the deficiency of the pancreatic hormone insulin. It is caused either by the decreased production of insulin or its malfunction. Insulin enhances the cellular uptake of glucose molecules in the blood. It also converts the glucose into glycogen in the liver and the muscles. So, in the absence of insulin, the concentration of glucose rises in the blood causing diabetes mellitus.