The Effects of Castration on the Induction of Experimental Gliomas in Male Rats

Pellets of 3,4-benzopyrene were implanted into the brain of equal numbers of normal and castrated male rats. The position of the implant was carefully controlled so that it impinged on the mitotically active sub-ependymal plate. A high proportion of glial tumours (77.8%) were induced in normal male rats. The effects of castration were to reduce the incidence of tumoures (50%) and to increase the time interval between implantation and death from cerebral tumour. The implications from these results, as to the possible roles of testosterone, are discussed.