Understanding link between polycystic ovary syndrome and insulin resistance

Understanding the link between Polycystic Ovary Syndrome (PCOS) and insulin resistance is the aim of a new project announced, funded by the charity WellBeing of Women.

It is known that women with PCOS have a 3-fold increase in their risk of developing type-2 diabetes, where the body does not produce enough insulin or cannot use insulin properly. Insulin resistance is an important factor in the condition, which is the most common female hormone disorder. PCOS affects between 5 and 10 per cent of women and is a major cause of infertility.

The new £97K project aims to identify a defective point on the insulin signalling pathway in women with PCOS. The researchers, from Imperial College London, hope this will enable the development of new therapies which target this part of the pathway, to counter the insulin resistance and the fertility problems that PCOS can cause.

Insulin is released from cells in the pancreas after eating and it signals insulin-sensitive tissues (such as fat and muscle) to take up glucose, keeping glucose levels in the bloodstream normal. In people with insulin resistance, normal amounts of insulin are not adequate to produce a normal glucose response, meaning that levels of insulin in the bloodstream need to be higher to achieve normal blood sugar levels.

Insulin resistance (and/or the compensatory excess of insulin in the bloodstream), may contribute to abnormalities in function of the ovaries that lead to many of the symptoms of PCOS. These include irregular periods, or no periods at all; fertility problems; weight gain; acne; and excessive hair growth (hirsutism).

A longer term concern is that insulin resistance also predisposes people to diabetes. In some patients the pancreas is unable, in the long-term, to produce enough insulin to compensate for the resistance of the tissues to insulin action. Consequently, blood sugar levels rise. What is not known is why PCOS and insulin resistance are so closely related.

The researchers hope that the new project will explain the link between PCOS and insulin resistance and how the link manifests itself at the level of individual cells.

The researchers will be looking at how ovarian cells metabolise glucose in women both with and without PCOS.

Professor Stephen Franks said: "PCOS gives rise to a range of symptoms. These may be very distressing not only because of problems with irregular periods and with fertility but also because of excess body hair, acne or alopecia. We still do not fully understand the underlying cause or causes of PCOS but insulin resistance plays an important part in many patients.

"These studies will give us the chance to look directly at the mechanism of insulin resistance at the level of an important target tissue - the ovary. We expect the results of these studies to give us information that will help to devise new and more effective methods of treatment for this very common hormone problem," he added.