cyclic-gmp and stilbene-oxide

The relationship between the activity of glutathione S-transferases (GSTs), especially the mu isozyme, and the production of responses to nitroglycerin (GTN) was investigated in rabbit aorta. GST mu isozyme activity was measured using trans-stilbene oxide (TSO) as a substrate. Each aorta was divided into four parts, two of which were frozen for enzymatic analyses while the remaining two were used to measure the effects of GTN (0.5 microM), i.e. the increase in cGMP levels and the corresponding relaxation. Thus, all three measures were obtained in each individual rabbit aorta. Eight different rabbits were studied. An excellent correlation was obtained between the rise in cGMP and the mu isozyme activity (r2 = 0.948). A good correlation was also obtained between TSO activity and the relaxation response to GTN. Total GST activity did not correlate well with either cGMP increases or percent relaxation. These observations indicate that the activity of the mu isozyme measured using TSO and not the total GST correlates with the responses to GTN in the in vitro rabbit aorta model.

Topics: Animals; Aorta; Cyclic GMP; Glutathione Transferase; Isoenzymes; Models, Biological; Nitroglycerin; Rabbits; Stilbenes; Vasodilation