Obesity, serum steroid levels, and pulsatile gonadotropin secretion in polycystic ovarian disease.

Serum binding capacity of sex-hormone binding globulin (SHBG-BC), steroid concentrations, and secretion patterns of LH and FSH were compared between groups of seven nonobese and seven obese patients with polycystic ovarian disease (PCOD). Obese patients with PCOD differed from those with normal weight in having very low SHBG-BC and elevated serum levels of free and albumin bound testosterone. Compared to healthy women in the follicular phase, both nonobese and obese patients with PCOD showed equally elevated serum levels of androstenedione, estrone, and albumin-bound and free estradiol. Pattern of gonadotropin secretion was studied from blood samples taken at 15 min intervals for 6 h. In 6 patients of both groups low pulses of FSH were found coincidently with pulses of LH. Serum level of LH showed a clear pulsatile pattern in all patients with PCOD, varying from 4.5 to 7.5 pulses per 6 h. The mean pulse rate in the groups of nonobese and obese patients with PCOD was similar, 5.9 pulses per 6 h. In the obese patients the mean LH levels were, however, less elevated and the pulse amplitudes were smaller than those in the nonobese patients. We suggest that this difference is due to high levels of biologically active testosterone in obese patients with PCOD.