PCOS and Insulin Resistance

Though 70% of PCOS sufferers have insulin resistance, I don’t have this myself. If you are one of those typical PCOS persons who are obese then you are most likely to have this. It is important to test for insulin resistance and glucose tolerance if you have symptoms of PCOS or if you are undergoing a blood test to diagnose PCOS. Most of the PCOS patients are obese and the major contributor of obesity in PCOS patients is Insulin Resistance.

What is Insulin Resistance?

As the name suggests, it means the inability of body to use insulin effectively. This will result in high blood insulin levels causing PCOS. Insulin is a hormone secreted by the pancreas gland. It is produced in large amounts after a meal and in smaller amounts between meals.

The main function if Insulin is to convert and control the energy from foods in the body after a meal. The food we consume comes in 2 major forms namely fats and carbohydrates. Carbohydrates comes in 2 major forms starch ( rice, potato, pasta..) and sucrose from carbonated drinks. Both are digested into glucose and then absorbed into the blood stream. In the same way, fats are digested into smaller fats and absorbed into the blood.

After glucose is absorbed into the blood, hormone insulin stimulates muscles and liver to absorb glucose and store it for later energy use. If you have insulin resistance, your body doesn’t absorb glucose from your blood effectively. You might think this will lead to high levels of glucose in the blood stream. But, what actually happens is your pancreas will start producing higher levels of insulin to control your glucose levels. Thus your pancreas starts working 3-5 times the normal rate and the insulin producing cells in pancreas will eventually wear out. Though the wear out period differs for each and every person, it is important to treat this condition as this might potentially result in Type 2 diabetes in the future. It is definitely preventable if treated promptly.

Fat breakdown usually occurs at a lower level of insulin (i.e. It occurs few hours after a meal). As the insulin levels are usually higher for a person with insulin resistance fat breakdown is eventually switched off resulting in weight gain. Without fat breakdown enlarged fat cells gets stored in your body which will cause variety of other problems.

Enlarged fat cells secrete a variety of other hormones which will act on the muscles and the muscles become more resistant to insulin. This will cause the pancreas gland to secrete larger further larger amounts of insulin in order to maintain the normal blood glucose level. Thus it becomes harder to achieve fat breakdown due to higher insulin levels.
For PCOS women it is easy to gain weight because the process of fat breakdown is halted and very difficult to lose weight despite diet and exercise.

How does insulin resistance cause PCOS?

The ovarian follicles are lined by two types of cells, theca cells and granulosa cells. Theca cells absorbs cholesterol out of the blood stream and, after a series of steps, turns it into androstenedione, a weak male hormone. Theca cells pass the androstenedione on to the adjacent granulosa cells where it is converted into oestrone, a weak oestrogen or female hormone and then into oestradiol, a strong oestrogen or female hormone.

In women with a genetic susceptibility, high levels of insulin in the blood stimulate an enzyme called cytochrome P450c 17-α in both the ovaries and the adrenal glands to produce increased amounts of male hormones. Yes, the increased levels of male hormones come from both the ovaries and the adrenal glands and hence ovarian removal will not fix your problem completely.

The high levels of insulin in the blood stream also stimulate the pituitary gland to produce increased amounts of LH. It does not, however, stimulate a surge in LH secretion. The higher baseline levels of LH stimulate the same enzyme, cytochrome P450c 17-alpha to produce even more male hormones, but only in the ovaries not the adrenal glands.
The developing follicle and egg do not become sensitive to stimulation by LH until the follicle has grown to a diameter of 9.5 mm.

High levels of insulin, however, cause the developing follicle and egg to respond to stimulation by LH at an earlier stage of development, at 4mm. diameter rather than at 9.5 mm. As no further development of the follicle is possible after LH stimulation, the growth of the follicle is therefore stopped at a diameter of 8 mm and the follicle is left too immature to ovulate. These immature follicles do not rupture as in normal ovulation and hence left as cysts.

When ovulation does not occur for some reason, both the theca cells and the granulosa cells lining the follicle should self-destruct by a process of "programmed cell death", known medically as apoptosis. This causes the follicle to collapse and disappear. In the polycystic ovary syndrome the granulosa cells self-destruct normally after failure of ovulation but the theca cells do not die because they are kept alive by high levels of insulin, preventing the follicle from collapsing, resulting in a cyst.

After failure of ovulation and after death of the granulosa cells, the theca cells that should have died continue to produce androstenedione. As there are no longer any adjacent granulosa cells to convert the androstenedione into estrogens, the theca cells convert the androstenedione into testosterone. In other words, for whatever reason a woman may have an ovarian cyst, the lining of the cyst will produce testosterone in most cases.

If you have PCOS due to high levels of insulin then it can be reversed by following proper diet and also by a medication named a metformin. It is vital to treat this insulin resistance to prevent yourself from the risk of cardiovascular diseases and diabetes.