Causes of PCOS
PCOS is the result of a hormonal imbalance, caused by a disorder in a woman’s endocrine system. This system is made up of all the body’s glands -- pituitary, pineal, thyroid, parathyroid, thymus, adrenal, and pancreas. Hormones secreted by these glands control such things as growth, metabolism, and reproduction. In women with PCOS, this system is not working properly. Scientists believe there are several potential causes of this hormonal imbalance.
For many years, PCOS was considered a direct result of high levels of male hormones in the body, although it was not understood exactly what caused these high levels. Researchers are now just beginning to understand the association between PCOS and the body’s overproduction of insulin. Many women with PCOS have hyperinsulinemia, a higher than normal amount of insulin in their bodies. Hyperinsulinemia results from insulin resistance.
Insulin resistance results from the body not metabolizing sugar well. Let’s take a closer look at the process, starting with the intake of food. As food enters your body, it is broken down into small components, including glucose, an important sugar that comes from carbohydrates. Glucose is a major source of quick energy for the body. When you eat foods high in carbohydrates, your body detects a rise in glucose and signals the pancreas to produce more insulin.
Together, glucose and insulin enter the bloodstream. The insulin fits into special “insulin receptors” in the cells. This allows the excess glucose to enter the cells and be used right away as energy or stored for future use. In the muscles and liver, glucose can be stored short-term as glycogen. In other tissues it can also be converted into fat for longer storage. To use an analogy, think of insulin as the key that unlocks the cell door so that excess glucose can enter and be converted to glycogen and stored for later use. When one has insulin resistance, it is as if the key no longer fits the lock. Consequently, the insulin is not able to fit into the insulin receptors, and excess glucose is not allowed to enter the cells. This causes a rise in both glucose and insulin levels in the blood.
In women with PCOS, these increased levels of glucose and insulin create an imbalance with other hormones. Subsequently, the body produces more male hormones and inhibits the ovaries from ovulating. This, in turn, causes the many PCOS-related symptoms. If left untreated, insulin resistance can lead to type II diabetes. Although insulin resistance is not found in every woman with PCOS, it is seen in many with PCOS, most prominently in those who are overweight.