Hyperinsulinemia

Hyperinsulinemia, or hyperinsulinaemia is a condition which there are excess levels of insulin circulating in the blood than expected relative to the level of glucose. While it is often mistaken for diabetes or hyperglycaemia, hyperinsulinemia can result from a variety of metabolic diseases and conditions. While hyperinsulinemia is often seen in people with type two diabetes mellitus, it is not the cause of the condition and is only one symptom of the disease. Hyperinsulinemia can be seen in a variety of conditions including diabetes mellitus type 2, in neonates and in drug induced hyperinsulinemia

Hyperinsulinemia is associated with hypertension, obesity, dyslipidemia, and glucose intolerance. These conditions are collectively known as Metabolic syndrome. This close association between hyperinsulinemia and conditions of metabolic syndrome suggest related or common mechanisms of pathogenicity. Hyperinsulinemia has been shown to "play a role in obese hypertension by increasing renal sodium retention". Insulin has a regulatory role in the transportation of cations across the cell membrane. Elevated circulating insulin levels, such as in the case of hyperinsulinemia, cause intracellular sodium concentrations to increase, and intracellular potassium concentrations to decrease. This alteration in cation concentrations both intracellularly and extracellularly contribute to hypertension. Since hypertension is related to all other conditions of metabolic syndrome it can then be extrapolated that cation transport is ubiquitously associated with obesity, dyslipidemia, and glucose intolerance as well. Furthermore, the alteration of cation transport across the membrane may serve as a marker for insulin resistance.

In type two diabetes, the cells of the body become resistant to the effects of insulin as the receptors which bind to the hormone become less sensitive to insulin concentrations resulting in hyperinsulinemia and disturbances in insulin release. With a reduced response to insulin, the beta cells of the pancreas secrete increasing amounts of insulin in response to the continued high blood glucose levels resulting in hyperinsulinemia. In insulin resistant tissues, a threshold concentration of insulin is reached causing the cells to uptake glucose and therefore decreases blood glucose levels. Studies have shown that the high levels of insulin resulting from insulin resistance might enhance insulin resistance.

Hyperinsulinemia in neonates can be the result of a variety of environmental and genetic factors. If the mother of the infant is a diabetic, and does not properly control her blood glucose levels, the hyperglycemic maternal blood can create a hyperglycemic environment in the fetus. To compensate for the increased blood glucose levels, fetal pancreatic beta cells can undergo hyperplasia. The rapid division of beta cells results in increased levels of insulin being secreted to compensate for the high blood glucose levels. Following birth, the hyperglycemic maternal blood is no longer accessible to the neonate resulting in a rapid drop in the newborn’s blood glucose levels. As insulin levels are still elevated this results in hyperinsulinemia. To treat the condition, high concentration doses of glucose are given to the neonate as required maintaining normal blood glucose levels. The hyperinsulinemia condition subsides after one to two days.