The Histochemical Distribution of Alcohol Dehydrogenase at Selected Sites in Four Species of Experimental Animal

Abstract

Abstract

In view of the ascribed involvement of alcohol dehydrogenase (ADH) in the metabolic activation of the carcinogen methylazoxymethanol, the distribution of this enzyme in the ear canal, duodenum, ileum, and colon of rats, mice, hamsters, and guinea pigs was examined by a histochemical method using 1-butanol as substrate. The technique described gave reproducible and specific results. While the distribution and intensity of staining for ADH differed from organ to organ, corresponding organs from each of the four species examined showed a remarkable degree of similarity in the distribution and intensity of staining. However, major differences are known to exist in the sensitivities of these organs in the four species to the carcinogenicity of methylazoxymethanol and/or its metabolic precursors 1,2-dimethylhydrazine and azoxymethane. Thus, we conclude that no specific correlation exists between the overall distribution of ADH, as determined by our histochemical method, and the organ specificity of these carcinogens.