Aortic Lipoprotein Lipase Activity in Relation to Species, Age, Sex, and Blood Pressure

It has been suggested that lipoprotein lipase (LPL) activity may play a role in the etiology of atherosclerosis. To determine whether there is an inverse relationship between arterial LPL activity and the tendency for arteries to become atherosclerotic, determinations were made of the activities of the enzyme in homogenates of the aortas of animals under conditions associated with a greater or lesser tendency for atherosclerosis to develop. It was found that the LPL activities of the aortas of old rats and rabbits were significantly lower than those of young animals of the same species, respectively. Rats, which are resistant to the development of atherosclerosis, manifested about twice the aortic LPL activities that rabbits did, the latter animals being notorious for the ease with which they develop the disease. This was true regardless of the age and sex of the animals compared. These results support the hypothesis that low arterial LPL activity may be associated with increased atherogenesis. Aortas of female rats or rabbits, however, showed no greater LPL activities than did aortas of males of the same species. Renal and desoxycorticosterone-salt hypertensions were accompanied by significant increases rather than decreases in aortic LPL activity. The latter results are not consonant with the aforementioned hypothesis.