Abstract
The treatment of hepatic microsomes with phospholipase A or phospholipase C decreased the drug hydroxylase activity. The exception was the aryl hydrocarbon hydroxylase in hepatic microsomes from 3‐methylcholanthrene pre‐treated rats. Its specific activity remained unchanged after phospholipase A digestion. In hepatic microsomes from phenobarbital pretreated rats the aryl hydrocarbon hydroxylase was not significantly increased and after phospholipase A or phospholipase C digestion, it decreased in both treated and control rats. The phenobarbital or 3‐methylcholanthrene induced p‐nitroanisole 0‐demethylase activity in liver microsomes decreased in a manner corresponding to the decrease in cytochrome P‐450 (P‐448) concentrations. The treatment of hepatic microsomes with phospholipase A or phospholipase C activated the membrane‐bound UDP glucuronosyltransferase both in control and drug‐treated rats. Phospholipase A increased the measurable UDP glucuronosyltransferase activity particularly in hepatic microsomes from 3‐methylcholanthrene pretreated rats. However, digestion with trypsin was necessary in order to detect the induction in UDP glucuronosyltransferase after phenobarbital pretreatment of rats. Other agents studied, such as phospholipase A or C, digitonin, cetylpyridinium chloride, or NaSCN, were unable to do this. Digestion with trypsin released considerable amounts of UDP glucuronosyltransferase activity into 27,000 g supernatant, especially from phenobarbital microsomes, whereas phospholipase A was more active in releasing UDP glucuronosyltransferase into 27,000 g supernatant from hepatic microsomes of 3‐methylcholanthrene pretreated rats. Membrane perturbating agents seem to differ in their action towards the hepatic microsomal membranes obtained from rats treated with phenobarbital or 3‐methylcholanthrene.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
