The permeability of aortic endothelium to 125I-BSA in hyperlipidemic hamster. Effect of histamine and serotonin.

The aortic permeability to 125I-bovine serum albumin (BSA) and the effect of histamine and serotonin were investigated in hamsters with diet-induced hyperlipidemia. Animals, fed a cholesterol- and butter-rich diet for five weeks, were sacrificed weekly and the level of serum cholesterol, the aortic permeability, and the morphologic aspect of the vessel wall, were analysed. During this interval, the cholesterolemia increased four-fold, and a progressive lipid accumulation in the intima was recorded. The permeability of the aortic wall was assessed by injecting 125I-BSA into the circulation and detecting the radioactivity in the aortic wall. The effect of the two vasoactive amines was determined by injecting histamine or serotonin concomitantly with the 125I-BSA. The results indicate that during the early stages of experimental hyperlipidemia in hamster, the aortic wall shows an increased permeability to albumin. The process is markedly augmented by histamine and serotonin, predominantly in the abdominal aorta.