Hormonal effects on glioblastoma multiforme in the nude rat model

Object. The authors studied the effect of gender and hormonal status on sur vival in nude rats implanted with human glioblastoma multiforme (GBM) cell lines. Methods. Nude rats received intracerebral implants of either wild-type U87M G cells or U87MG cells transfected with the gene for endothelin-1 (U87/ET-1 ). In the initial study, survival was compared in males and females for eac h of the two cell lines. The six second-phase study groups were composed of : 1) males, 2) females; 3) ovariectomized females; 4) sham ovariectomized f emales; 5) ovariectomized rats given 10 mu g/day estradiol benzoate for 21 days; and 6) ovariectomized rats given 20 mg/kg/day progesterone for 21 day s. All rats in the second phase were implanted with U87/ET-1 cells. Animals were killed when they exhibited initial signs of neurological deterioratio n. Female nude rats survived longer than male rats implanted with either U8 7 or U87/ET-1 cells. In the second phase, ovariectomized, male, and progest erone-treated rats died at approximately 19 days, whereas the female, sham- treated, and estrogen-treated animals died 23 to 25 days after tumor cell i mplantation. Conclusions. The authors demonstrate that female nude rats implanted with h uman GEM cells have a survival advantage over male rats and that estrogen p rovides the advantage.