Enhancement of cytosolic carboxylesterase by phenobarbital in the rat.

Previously suggested identity of soluble hepatic carboxylesterase and cytosolic aldehyde dehydrogenase was studied in the liver of the rr and RR rat substrains after phenobarbital administration. Results showed over 30% increase of carboxylesterase activity in all animals treated with phenobarbital. The total aldehyde dehydrogenase activity was increased only in RR substrain. These animals had no similar enhancement in the activity of carboxylesterase. The results indicate that the two enzymes are not identical.