Effects of intermittent high-intensity exercise and carbohydrate supplementation on IGF-1 and glycogen of Wistar rats.
OBJECTIVE
The aim of this study was to analyze the association between glucose infusion during intermittent physical exercise and its metabolic effects on rats.


METHODS
Forty male rats were divided into eight groups based on training (intermittent), exercise and carbohydrate intake (glucose 20%): TEC (trained exercised with carbohydrate), TES (trained exercised without carbohydrate), TNC (trained non-exercised with carbohydrate), TNS (trained non-exercised without carbohydrate), UEC (untrained exercised with carbohydrate), UES (untrained exercised without carbohydrate), UNC (untrained non-exercised with carbohydrate) and UNS (untrained non-exercised without carbohydrate). The training and/or exercise protocol consisted of the rats running on a treadmill for 1 min above the lactate threshold, or running below the lactate threshold for 30s, intermittently for 30 min. Blood was analyzed for glycemia, lactate and IGF-1. Muscle and liver glycogen were measured (T2).


RESULTS
Glycemia was found to be different in T2 compared to T1 in the TEC, TNC, UEC and UNC groups. Lactate was higher in T2 than in T1, but remained within the lactate threshold. Glycogen showed higher concentrations in the trained groups and, whether trained or not, in the supplemented groups. IGF-1 levels were higher in exercised rats independent of supplementation or glycogen levels. Trained rats showed lower IGF-1 when exercising than did the untrained animals.


CONCLUSIONS
We conclude that intermittent exercise is beneficial in preventing a trained lactate pool, and that, in association with glucose supplementation, intermittent exercise will be efficient both in preventing a trained lactate pool and in maintaining sufficient glycemia levels. Exercise raises IGF-1 levels, whereas training inverts this relationship.
Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. viviannho@yahoo.com.br
Vivian Treichel
VT
Giesel
Mateus
M
Reche
Lolita
L
Schneider
Lucas Campos
LC
Araújo
Rosana
R
Scalco
Helena
H
von Eye Corleta
Edison
E
Capp
D000818:Animals; D050260:Carbohydrate Metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D006003:Glycogen / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D019344:Lactic Acid / Q000097:blood; D008112:Liver Glycogen / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal; D005082:Physical Exertion; D051381:Rats; D017208:Rats, Wistar
D004040:Dietary Carbohydrates; D008112:Liver Glycogen; D019344:Lactic Acid; D007334:Insulin-Like Growth Factor I; D006003:Glycogen