The medium- and long-term effects of gestrinone and danazol on the end
ometrium were examined in 36 patients with endometriosis. Endometrial
biopsies were taken from each patient before treatment and after 3 and
6 months of treatment with 600 mg danazol daily (n = 17) or with 2.5
mg gestrinone twice weekly (n = 19). Endometrial samples were analysed
by light, scanning and transmission electron microscopy. At 3 months'
treatment the endometria of patients treated with danazol appeared mo
re atrophic than those of the women treated with gestrinone; some cell
organelle involution was evident in all patients. After 6 months of t
reatment a marked atrophy was observed in patients of both treatment g
roups. A complete involution of cytoplasmic organelles with cytoplasmi
c collapse and a shift of nucleoplasmic ratio in favour of the nucleus
occurred in patients treated with danazol; the cytoplasmic organelle
involution was less marked in patients treated with gestrinone. Compar
ed with gestrinone, danazol induces more rapid endometrial atrophy, wi
th greater impairment of the cytoplasm and cell secretory activity.