Insulin is a peptide hormone secreted by the β cells of the pancreatic islets of Langerhans and maintains normal blood glucose levels by facilitating cellular glucose uptake, regulating carbohydrate, lipid and protein metabolism and promoting cell division and growth through its mitogenic effects.
Insulin resistance is a state in which there are impaired biological and physiological responses to insulin in tissue. Insulin resistance can be caused by prereceptor, receptor, or postreceptor abnormalities.
When the person has insulin resistance, his body can’t use insulin properly. At first, the pancreas makes extra insulin to make up for it. But, over time his body isn't able to keep up and can't make enough insulin to keep the blood glucose at normal levels.
Generalized insulin resistance occurs primarily as a result of obesity, a consequence of caloric excess, physical inactivity, genetics, and age.
Obesity is the leading cause of insulin resistance, and obese individuals tend to have higher plasma FFAs as a result of decreased suppression of lipolysis by insulin resistance.
Insulin resistance: A decrease in the ability of insulin to stimulate body glucose disposal
