Effects of potassium-aspartate salt administration on glycogen use in the rat during a swimming stress.
The ergogenic effect of aspartate salts on performance during prolonged exercise is still controversial. Potential mechanisms of the suggested ergogenic effect of aspartate on exercise performance are a sparing of muscle glycogen stores or its faster resynthesis during exercise. The purpose of this study was to determine whether aspartate causes a sparing of muscle glycogen during exercise. Six groups of rats were studied: one group received a single injection of aspartate (1 g.kg-1, IP) and was then sacrificed at rest, a second group of aspartate-treated rats was sacrificed after a 60-min swim. The third and fourth groups were given an injection of physiological saline and then sacrificed respectively at rest and after a 60-min swim. The fifth and sixth groups were given an aspartate or a saline injection and then sacrificed after swimming to exhaustion. The exhaustion times after saline (178.9 +/- 38.2 min) and aspartate (174.4 +/- 45.2 min) were not significantly different. Results did not confirm an ergogenic effect of a single dose of aspartate on swimming endurance in the rat. Aspartate-treated rats had a significantly lower plasma FFA concentration after swimming to exhaustion when compared to control rats (respectively, 0.70 +/- 0.25 vs. 1.16 +/- 0.45 mM). Also, the results of the present study do not support the hypothesis of a sparing of muscle or liver glycogen with aspartate, because a similar content of glycogen remained in the muscles and liver of control rats after a 60-min swim or after swimming to exhaustion.
Trudeau
F
F
Département des sciences de l'activité physique, Université du Québec à Trois-Rivières, Canada.
Murphy
R
R
D000641:Ammonia / Q000097:blood; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology*; D001786:Blood Glucose / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006003:Glycogen / Q000097:blood*; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007773:Lactates; D001224:Aspartic Acid; D019344:Lactic Acid; D000641:Ammonia; D006003:Glycogen