Obesity and Its Role in Poly cystic Ovary Syndrome*

Abstract

To examine the mechanism by which obesity influences ovulation, 55 patientswith oligo- or anovulation were studied. Parameters measured in serum were sex steroid-binding globulin (SSBG), testosterone (T), PRL, LH, FSH, and estradiol (E₂). The women were divided into 2 groups: an obese group (group 1), greater than 145‰ of ideal body weight, and a normal weight group, less than 120‰ ideal body weight. SSBG was measured by saturation analysis. T, LH, FSH, PRL, and E₂ were measured by RIA. SSBG group 1 levels were 7.14 ng dihydrotestosterone bound⁄ml compared to 14.7 ng dihydrotestosterone bound ⁄ml in group 2 (P < 0.05). There were no significant differences in FSH, T, or E₂. The correlation of body weight vs. SSBG in all patients was r =−0.62. In these 2 groups, the SSBG was significantly lower in the obese patients compared to that in the normal weight patients, independent of T or E₂ levels. SSBG correlated negatively with body weight,suggesting that obesity has an influence on SSBG levels independent of hormonal status. When SSBG is lowered, there may be an increase in free T which, by inhibiting follicularmaturation, may begin the sequence of events seen in polycystic ovary syndrome.