δ4-Reductase and Sulfokinase Activities of Rat and Sheep Liver Preparations.

Summary Sheep liver preparations demonstrated a greater capacity to conjugate p-nitrophenol than dehydroepinandrosterone based on an equivalent unit of liver. The opposite was observed for rat liver. Rat liver was also able to conjugate more dehydroepi-androsterone than was sheep liver. This species difference in the ability to conjugate various substrates was attributed to the presence of ionone derivatives in the feed of ruminant animals. Rat liver displayed a greater δ4-reductase activity than did sheep liver for cortisol, cortisone, and corticosterone. This species difference was attributed to dietary differences plus other metabolic differences known to exist in ruminant animals. The results of this investigation were discussed in terms of what has been previously observed for glucuronosyl transferase activity for sheep, dog, and rat.