[Ultrastructural alterations of rat ventral prostate after peplomycin sulfate administration (author's transl)]

Ultrastructural alterations of rat ventral prostate were studied following the administration of peplomycin sulfate (NK631) to evaluate the efficacy of this drug to the human prostatic carcinoma. The rats as experimental animals were divided into 3 groups: control, castrated and NK631 administration ones with 5 mg per kg per day. Rat body weight and ventral prostatic weight were measured at 4, 7 and 14 days after the treatment. Simultaneously prostatic tissue samples were obtained for electron microscopic study. The ventral prostatic weight and body weight ratio (VBW) was utilized in respect to the prostatic weight to compared the experimental groups with control ones. The VBW was significantly decreased at 14 days after castration. NK631 administration showed only minor decrease at 14 days duration. However, statistics for control and NK631 were different. Ultrastructurally, normal rat ventral prostate demonstrated to contain abundant rough endoplasmic reticulum and well developed GOLGI apparatus and round nucleus. After castration, ventral prostatic cells lost their normal cytoplasmic configuration with the atrophy of rough endoplasmic reticulum and GOLGI apparatus, while secondary lysosomes were occasionally found in the cytoplasm. During the course of NK631 administration, the changes were detected in the cytoplasm with marked vacuolization and degeneration of rough endoplasmic reticulum as well as disappearances of cytoplasmic matrix. Nucleus was also affected with the marked indentation of nuclear membrane and disappearance of nucleoplasm. From the present preliminary investigation, NK631 could induce the cytostatic changes to rat ventral prostate. Therefore, NK631 would be suggested to contribute to the treatment of prostatic carcinoma. It is hoped that as more experimental studies are processed, a deeper understanding of the effect of NK631 would be clarified.