Comparative biochemical and morphometric changes associated with induction of the hepatic mixed function oxidase...

Area of Science:

• Pharmacology
• Biochemistry
• Toxicology

Background:

• The cytochrome P-450-dependent mixed function oxidase system is crucial for drug metabolism.
• SK&F 86002 is known to inhibit both cyclooxygenase and 5-lipoxygenase pathways.
• Understanding drug-induced enzyme induction is vital for predicting drug interactions and toxicity.

Purpose of the Study:

• To characterize the induction of the rat hepatic cytochrome P-450 system by SK&F 86002.
• To compare the induction profile of SK&F 86002 with phenobarbital, a known inducer.
• To quantify morphological changes associated with hepatocellular hypertrophy induced by these compounds.

Main Methods:

• Rats were administered varying doses of SK&F 86002 or phenobarbital for 3 or 14 days.
• Key parameters measured included liver-to-body weight ratio, hepatic microsomal protein, and cytochrome P-450 content.
• Enzyme activities such as ethoxycoumarin-O-deethylase (ECOD) and leukotriene B4 hydroxylases were assessed.
• Ultrastructural morphometry was performed on liver tissues.

Main Results:

• SK&F 86002 increased liver-to-body weight ratio and ECOD activity in a dose-dependent manner.
• Phenobarbital also increased liver-to-body weight ratio and ECOD activity, with higher doses showing more pronounced effects.
• On day 14, phenobarbital increased cytochrome P-450 content across all tested dosages.
• Neither compound significantly affected leukotriene B4 hydroxylase activities.

Conclusions:

• SK&F 86002 is an effective inducer of the rat hepatic cytochrome P-450 system.
• The induction profile of SK&F 86002 shares similarities with phenobarbital, suggesting overlapping mechanisms.
• The findings contribute to understanding the metabolic impact of SK&F 86002 and its potential for drug interactions.