Effect of vitamin A deficiency on pulmonary defense systems of guinea pig lung.

Vitamin A deficiency causes a significant decrease in superoxide dismutase, glutathione peroxidase and GSH levels. Simultaneously, it causes a marked increase in Phase I microsomal oxidation (cytochrome P-450, aniline hydroxylase, PNA-O-demethylase) as well as in enzymatic and non-enzymatic lipid peroxidation in lung. Among Phase II enzymes, cytosolic chlorodinitrobenzene glutathione-S-transferase (CDNB-GST) activity showed a significant increase whereas microsomal UDP-glucuronyl transferase and cytosolic p-nitrobenzoyl chloride- and dichloro nitrobenzyl chloride-S-transferase activities showed variable decrease reflecting an imbalance in the Phase I and Phase II enzyme systems. CDNB-GST and non-Se-GSH-Px, registered a parallel rise with pulmonary cytochrome P-450, aniline hydroxylase and O-demethylase, as an adaptive response to elevated Phase I enzyme activity.