Effects of danazol on pulsatile gonadotropin patterns and on serum estradiol levels in normally cycling women.

The effect of danazol on pulsatile luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2) secretion was examined in eight premenopausal women by serial blood sampling on day 10 of the control and first treatment cycles and during 2 subsequent months of treatment. The mean frequency of LH pulses decreased, while the mean pulse amplitude and increment increased (P less than 0.05). The mean LH concentrations were significantly suppressed in four of eight subjects. The mean frequency of E2 pulses, mean increment, and mean integrated area were decreased (P less than 0.05). The mean integrated FSH area did not change significantly during treatment, and we were not able to demonstrate unequivocal FSH pulses. We conclude that danazol in premenopausal women (1) lowers serum E2 concentrations by decreasing the frequency and increment of E2 pulses, (2) prevents compensatory gonadotropin rise, and (3) lowers the frequency but increases the amplitude and increment of LH pulses. The latter change reflects probably divergent effects of the drug on the pituitary and hypothalamus and results in an inconsistent lowering of basal LH levels.