Effects of exercise on plasma lipoprotein levels and endothelium-dependent vasodilatation in young and old rats.
Effects of treadmill exercise (1 h.day-1 for 12 weeks) on the mechanical properties of isolated aortae and plasma concentrations of low and high density lipoprotein cholesterols ([LDL-C]pl and [HDL-C]pl, respectively) were investigated in young (16 weeks) and old (98 weeks) rats. With aging, [LDL-C]pl increased and acetylcholine (ACh) elicited greater endothelium-dependent relaxations of the aorta in old rats than in young rats. Also, in all groups of rats tested (young, old, exercised and nonexercised), the increase in the [LDL-C]pl correlated with an increase in the sensitivity of relaxation of the aorta to ACh. On the other hand, a greater [HDL-C]pl was associated with a smaller relaxation response to ACh in young rats only when exercised and nonexercised groups were combined. The increase in [HDL-C]pl with aging, however, did not correlate with the extent of ACh-induced relaxation. Exercise in old rats reduced [LDL-C]pl and the extent of ACh-induced relaxation of the aorta. Therefore, [LDL-C]pl appeared to be closely related to the extent of endothelium-dependent relaxation in response to ACh in the aorta. The [LDL-C]pl also correlated with the gain in mass of the rat. Exercise in old rats reduced the body mass and was accompanied by a decrease in [LDL-C]pl.
Hashimoto
M
M
Department of Physiology, Shimane Medical University, Japan.
D000109:Acetylcholine / Q000502:physiology; D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001011:Aorta / Q000502:physiology; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D008074:Lipoproteins / Q000097:blood* / Q000502:physiology; D008075:Lipoproteins, HDL / Q000097:blood / Q000502:physiology; D008077:Lipoproteins, LDL / Q000097:blood / Q000502:physiology; D010805:Physical Conditioning, Animal; D051381:Rats; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D000109:Acetylcholine