When a microcapsule preparation of cetrorelix was compared with microcapsules of agonist [d-Trp6]-LH-RH in rats bearing Dunning R-3327H prostate carcinoma, cetrorelix caused greater inhibition of prostate cancer growth than [d-Trp6]-LH-RH27, and decreased testosterone levels to non-detectable values, and LH levels were also diminished. This evidence concerns the gene GNRH1 and prostate carcinoma.