title: Initial events in radiation-induced atheromatosis. III. Effect on lipase activity.
abstract: Treatment of large blood vessels with ionizing irradiation leads to the development of atheromatosis when the serum lipid levels are sufficiently high. In order to answer the question whether a disturbed lipid clearance in the arterial wall plays a role in the accumulation of the lipids it was of interest to examine the effect of X-irradiation on the lipase activity. Triglycerol lipase was tested in a homogenate from rabbit carotid arteries, glycerol-tri-oelate was used as a substrate and the hydrolysis assayed at pH 6.4 at 37 degrees C. Under the conditions used, an hydrolytic activity could be measured of 7.5 nmoles . mg prot-1 . hr-1. The lipase activity was also tested in the carotid arteries obtained from rabbits which had been locally irradiated with 20 Gy of X-rays. No clear radiation effect on the lipase activity was found 4, 8, 20, 24 and 72 hours after irradiation. The accumulation of lipids is thought to be caused by a higher influx of lipids from the serum as a result of endothelial damage by X-irradiation rather than a defect in the clearance capacity of the arterial wall.
mesh_terms: D000818:Animals; D001158:Arteries / Q000201:enzymology / Q000528:radiation effects*; D001161:Arteriosclerosis / Q000201:enzymology* / Q000209:etiology; D004727:Endothelium / Q000528:radiation effects; D008049:Lipase / Q000032:analysis*; D008055:Lipids / Q000097:blood; D011817:Rabbits; D011833:Radiation Injuries, Experimental / Q000201:enzymology*; D013997:Time Factors
chemical_list: D008055:Lipids; D008049:Lipase