THE ANTIHYPOXIC ACTION OF ANTIOXIDANT BHT MEDIATED VIA NITRIC-OXIDE -A STUDY OF EPR SIGNALS IN TISSUES OF RATS OF DIFFERENT AGES

The effects of a single administration of BHT on the low-temperature E PR signals of heart and blood were studied in the experiments on adult (4-6 mo) and old (24-26 mo) male Wistar rats. The decrease of the sig nal of iron-sulphur proteins of heart mitochondrial electron-transport chains (g=1.94) takes place during the first 6 h after BHT injections while the free-radical semiquinone signal (g=2.003) tends to increase . Since the intensity of the EPR signal of mitochondrial iron-sulphur proteins (ISP) is directly proportional to the amount of these protein s in the reduced form, it means that BHT increases oxygenation of the heart tissue. In the spectra of the animals' blood, the ratio of the i ntensity of the signal of transferrin (g=4.3) to that of ceruloplasmin (g=2.05) decreased after the injections of BHT. In addition, the BHT- induced EPR signal of the NO-hemoglobin complex arose in the animals' blood. The intensity of this signal was lower in the case of old rats. As hypoxia/ischemia is known to impair heart mitochondria and trigger superoxide release, BHT appears to perform indirect antioxidative pro tection by means of fostering the extent of oxygenation of heart cells via NO-cGMP-mediated mechanisms.