Distribution and kinetic properties of alcohol and aldehyde-dehydrogenase in the rat testis.

The distribution of both alcohol (ADH) and aldehyde-dehydrogenase (ALDH) was studied in the rat testis. Testicular ADH was mainly localized into the interstitial tissue. Testicular ALDH activity was distributed between the interstitial tissue and the seminiferous tubules with greater activity measured in the former component. The apparent Km for ADH in the whole testis was greater than that measured in the interstitial tissue. A low Km value was determined for ALDH in the seminiferous tubules, compared to a higher mean Km value for this enzyme in the interstitial tissue of the testis. The study shows that interstitial tissue possesses both ADH and ALDH, which are essential for the respective metabolism of ethanol and acetaldehyde, and that the seminiferous tubules possesses greater affinity for the metabolism of acetaldehyde than that of the interstitial tissue.