Pathophysiology of polycystic ovarian disease: new insights.

The incidence of polycystic ovarian disease (PCOD) varies from 0.6 to 92%, depending on the parameters analysed, PCOD has been reported to appear in association with Cushing's Syndrome, adrenal hyperplasia, hypothyroidism, adrenal and ovarian tumours and some genetic abnormalities. The controversy regarding the pathophysiological mechanism underlying the disease still persists. Critical evaluation of old data, assessment of new findings concerning the possible role of insulin, growth factors and their binding proteins, and extrapolation of neuroendocrinological experiments enabled the construction of a concise hypothesis of the pathophysiology of PCOD. According to this hypothesis, PCOD is a multifactorial disease. The sequence of events finally leading to clinical manifestation of the disease (hyperandrogenism, abnormal luteinizing hormone pulsatility pattern and ovulation disturbances) may originate in different organs or be triggered by different mechanisms. It may stem from the adrenals, the hypothalamus or higher central nervous system centres, or from the ovary itself; it may originate from excess of fat tissue usually combined with hyperinsulinism; or may be the result of a net increase in active growth factors. Each of the above disturbances probably appears early in life, much before the clinical signs of the disease are evident. Predisposing factors such as gestational diabetes of the mother, childhood obesity, borderline adrenal hyperplasia and late menarche have to be looked for as early as possible in order to prevent the late consequences of the disease, such as increased risk of infertility, endometrial and breast cancer and cardiovascular disease.