[Action of retinoic acid on lipid peroxidation in rat liver microsomes in vitro].

It has been shown in experiments in vitro that preincubation of rat liver microsomes with an ethanol solution of all-trans-retinoic acid in the final concentration 7.0 X 10(-5) M results in a decrease of both NADPN-dependent and spontaneous lipid peroxidation (to 53 and 70% of control, respectively) but did not influence ascorbate-dependent lipid peroxidation. Retinol at the same concentration induces more pronounced inhibition of all types of microsomal lipid peroxidation. The rate of NADPN-dependent lipid peroxidation decreases linearly as the retinoic acid concentration in the incubation medium is raised, whereas the rate of ascorbate-dependent lipid peroxidation drastically lessens only after the retinoic acid concentration in the medium is increased to 1.4 X 10(-4) M. The data obtained provide evidence in favour of the concepts of a possible role of vitamin A in LPO regulation in the body and point to the necessity of taking into consideration the antioxidant properties of retinol and retinoic acid while analysing their pharmacological action.