Relationship between oxidative stress and hepatic phosphoglucomutase activity in rats

Area of Science:

• Biochemistry
• Toxicology
• Enzymology

Background:

• Oxidative stress is implicated in cellular damage.
• Hepatic enzymes play crucial roles in metabolism and detoxification.
• Understanding enzyme inactivation mechanisms is vital for toxicology.

Purpose of the Study:

• To investigate the relationship between oxidative stress and hepatic enzyme inactivation in rats.
• To identify specific hepatic enzymes affected by oxidative stress.
• To elucidate the mechanism of enzyme inactivation by lipid peroxidation products.

Main Methods:

• Rats were administered oral lipid peroxidation products and intraperitoneal pro-oxidative drugs.
• Oxidative stress was assessed using thiobarbituric acid (TBA) tests and tocopherol level reduction.
• Hepatic phosphoglucomutase activity was measured.
• Primary rat hepatocytes were cultured to study aldehyde effects on enzyme induction.

Main Results:

• Oral administration of secondary linoleic acid peroxidation products induced oxidative stress and decreased hepatic phosphoglucomutase activity.
• Several pro-oxidative drugs (CCl4, alcohol, paraquat, phenobarbital, thiopental, methylcholanthrene) increased TBA values and decreased phosphoglucomutase activity.
• Aldehydes from lipid peroxidation significantly suppressed dexamethasone-induced phosphoglucomutase activity in cultured hepatocytes.

Conclusions:

• Oxidative stress, induced by lipid peroxidation products and certain drugs, inactivates hepatic phosphoglucomutase in rats.
• Aldehydes generated during lipid peroxidation are likely responsible for inhibiting the hormonal induction of phosphoglucomutase.