GLUTATHIONE TRANSFERASE-ACTIVITY IN HUMAN VESSELS AND IN CULTURED ARTERIAL SMOOTH-MUSCLE CELLS

Glutathione transferases play an important role in the detoxification of many different endogeneous and exogenous compounds such as metaboli tes of polycyclic aromatic hydrocarbons (PAH) of cigarette tar. There is evidence that PAH may be atherogenic. The glutathione transferase a ctivity towards trans-stilbene oxide (GST-tSBO) can be separated in bl ood in GST-positive and GST-negative phenotypes. We have previously su ggested that the GST-negative phenotype may be associated with a highe r morbidity in intermittent claudication among middle aged smokers. In the present study, GST-tSBO could easily be measured in human, rabbit and bovine arterial smooth muscle cells (SMC) in culture. The level o f GST-tSBO was higher in rabbit than in bovine SMC. It was stable in b ovine SMC during 5 cell passages and it could be induced twofold by lo ng-time incubation with dimethylsulfoxide-soluble particulate matter f rom cigarette smoke or 3,4-benzo(a)pyrene. There was a positive correl ation between the level of GST-tSBO in blood and in ''healthy'' arteri al and venous tissue from individuals operated with coronary bypass. T he enzyme levels in arterial tissue were lower than in venous tissue. GST-tSBO in atherosclerotic segments of human arteries was lower than in ''healthy'' segments from the same artery. These findings suggest t hat the arterial wall may have a low defense against toxic compounds t hat may decrease further as atherosclerosis proceeds. It is concluded that SMC are suitable for the study of the effects of PAH in relation to GST-tSBO and that the enzyme activity in blood will reflect the ind ividual GST-tSBO phenotype also in vascular tissues.