SERUM IMMUNOREACTIVE LEPTIN CONCENTRATIONS IN WOMEN WITH POLYCYSTIC-OVARY-SYNDROME

Recent data in the mouse demonstrate that leptin, a protein hormone pr oduced by fat cells, is required for fertility. In the absence of lept in the mice become obese, diabetic and infertile. Polycystic ovary syn drome (PCOS), a common cause of infertility in women, is associated wi th obesity and insulin resistance. Because of the increased frequency of PCOS in obese women we tested the hypothesis that alterations in se rum leptin concentrations might be associated with PCOS. Immunoreactiv e leptin concentrations were measured in 58 women with PCOS and 70 reg ularly menstruating (control) women. As has previously been shown ther e nias a positive correlation between leptin levels and body mass inde x (BMI). Although the leptin levels in the majority of women with PCOS fell within the control range, 29% of PCOS women had leptin levels ab ove the 99% prediction interval for their BMI and none had low leptin levels. There were also positive correlations of leptin levels with fr ee testosterone and insulin sensitivity in control women. In women wit h PCOS, 13% and 9.5% exhibited higher than expected leptin concentrati ons with respect to free testosterone and insulin sensitivity, respect ively. Insulin resistant PCOS women had higher leptin levels than cont rols. The data demonstrate that a substantial proportion of women with PCOS have leptin levels that are higher than expected for their BMI, free testosterone and insulin sensitivity. These results suggest that abnormalities in leptin signaling to the reproductive system may be in volved in certain cases of PCOS.