The intra-acinar distribution patterns of alcohol-dehydrogenase activity in the liver of juvenile, castrated and testosterone-treated rats.

Rat liver alcohol dehydrogenase shows characteristic sex-differences with respect to activity and heterotopy. For the recognition of gonadal influences on the intra-acinar distribution patterns luminometric determinations of ADH activity were carried out on 50-150 ng lyophilized liver tissue samples which had been microdissected along the sinusoidal length. Juvenile rats of both sexes showed equally high alcohol dehydrogenase activity, which surpassed the adult values by a factor of 2 in males and 1.3 in females. The distribution pattern was rather flat, with a weak maximum at the beginning of the last third of the sinusoid. Castration of adult male and female rats resulted in an increase of alcohol dehydrogenase activity to around the prepubertal values. The intra-acinar profiles showed a gradual increase in activity from low periportal values to a peak near the perivenous zone. Only the hepatocytes directly adjacent to the efferent venule showed an even lower activity. Administration of testosterone to castrated animals had no effect on the ADH activity in males and resulted in only a slight decrease of enzyme activity in females. The intra-acinar distribution patterns showed an intermediary peak at the end of the second third of the sinusoidal length in males and a gradual increase of activity, beginning periportally, in the direction of the perivenous zone in females. The present findings on total activity of ADH and its distribution patterns in the liver are considered to be the result of complex hormonal alterations rather than a specific effect of testosterone.