Hydrolase activities in the rat aorta. III. Effects of regular swimming activity and its cessation.

Abstract

SUMMARY It is possible that one of the consequences of regular physical activity could be a change in vascular metabolism. We studied the effects of regular swimming activity on specific activities of aortic hydrolases of male rats. Enzymes included: neutral a-glucosidase and lysosomal /3-galactosidase, JV-acetyl-/}-glucosaminidase, cathepsin C, acid a-glucosidase, and acid cholesteryl esterase. After 8 or 16 weeks of a 1-hour/day swimming protocol, specific activities of four of the six aortic enzymes studied were increased over control levels, increases ranging from 7 to more than 42%. Acid cholesteryl esterase was one of the enzymes most affected by the exercise, increasing 25-30% above control levels. An 8-week sedentary period, after 8 weeks of a swimming regimen, resulted in return of the activity of acid cholesteryl esterase, but not those of the other hydrolases, to control levels. Decreases in body weight, blood pressure, and serum lipid levels also occurred in the swimming rats. Weight reduction per se was excluded as an explanation for the increases in aortic enzymes or decrease in serum cholesterol found with swimming. These findings show that regular physical activity is yet another factor with discrete and significant effects on the catabolic activity of vascular tissue. Ore Res 45: 548-553, 1979VIGOROUS exercise appears to be associated with a reduced prevalence of death from coronary heart disease in man (Paffenberger and Hale, 1975); less extreme exercise has not been so clearly related. Apart from the question of degree of exercise, it remains uncertain whether exercise itself is protective or whether it results in a favorable clustering of other factors associated with reduced risk. Among the latter are a decreased total serum cholesterol level (including decreased low density lipoproteins and increased high density lipoproteins), a decreased serum triglyceride level (Lopez-S et al., 1974;Fletcher and Cantwell, 1974;Wood et al., 1976;Cantwell, 1978), reduced systolic and diastolic blood pressure levels (Scheuer and Tipton, 1977), and increased vital capacity (Kannel, 1967). Similar decreases in serum lipids and blood pressure with swimming or running activity have been described for the rat (Papadopolou° et al., 1969;Tipton et al., 1977).We recently (Wolinsky and Fowler, 1978) have emphasized the importance of understanding the direct effects of putative risk factors for vascular disease on cellular metabolism of the blood vessel wall in addition to noting the levels of certain circulating lipoprotein classes, the blood pressure

Effects of Stress and Exercise on Plasma Corticosterone, Plasma Cholesterol, and Aortic Cholesterol Levels in Rats

“…The fact that Group D running animals were significantly higher than the basal level indicates that running per se led to increases in aortic cholesterol. In contrast, Wolinsky et al (21) found that forced swimming (1 hr/day for 8 weeks) resulted in increased levels of an enzyme (acid cholesteryl esterase) involved in the catabolism of cholesterol by the aorta. This would seem to be contradictory to the present results.…”

A proposal linking clearance of circulating lipoproteins to tissue metabolic activity as a basis for understanding atherogenesis.

“…Aortic ACE activity is increased in rats on a chronic swimming regime, but liver and kidney acid lipase activities are unchanged (Wolinsky et al, 1979). Clearance of 125 I-labeled LDL from the circulation of these rats also does not differ from that of normal sedentary animals (Table 1; Wolinsky et al, 1980).…”

“…Hypertension, for example, is a potent stimulus to acid esterase activity in the rat aorta, and the activity returns to normal when the animal is returned to a normotensive state (Wolinsky et al, 1978b). Unlike exercise, however, hypertension results in damage to the wall in association with these enzyme increases (Wolinsky et al, 1979). No information is yet available on LDL clearance in hypertensive humans or experimental animals.…”