Uptake and secretion of carcinogenic chemicals by the dog and rat prostate

Because the prostate of laboratory animals seems relatively resistant to the carcinogenic effects of systematically administered chemicals--an observation of some significance in attempts to establish the etiology of human prostatic adenocarcinoma and to produce animal models of prostatic cancer--we studied the penetration of eight carcinogenic chemicals into both the prostate gland and the prostatic secretion of the dog and the rat. The eight chemicals were 3-methylcholanthrene, 7,12-dimethylbenz[a]anthracene, N-hydroxyurethane, aflatoxin B1, 3-amino-1,2,4-triazole, 2-acetylaminofluorene, N-Methyl-N'-nitro-N-nitrosoguanidine, and cadmium. In both species all eight substances and/or their metabolites were found to rapidly enter the prostate, and all except cadmium were recovered from prostatic fluid. Thus, although the levels in prostatic fluid did not always reflect levels in the gland, there was little if any barrier to the penetration of these chemicals into the gland. The apparent relative refractoriness of the prostate to systematically administered carcinogenic chemicals cannot be due to failure of such substances to enter the gland.