Diminished hormonal responses to exercise in trained rats
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Diminished hormonal responses to exercise in trained rats. / Galbo, H; Richter, Erik A.; Holst, J J; Christensen, N J.
In: Journal of Applied Physiology, Vol. 43, No. 6, 1977, p. 953-958.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Diminished hormonal responses to exercise in trained rats
AU - Galbo, H
AU - Richter, Erik A.
AU - Holst, J J
AU - Christensen, N J
PY - 1977
Y1 - 1977
N2 - Male rats (120 g) either were subjected to a 12-wk physical training program (T rats) or were sedentary controls (C rats). Subsequently the rats were killed at rest or after a 45- or 90-min forced swim. At rest, T rats had higher liver and muscle glycogen concentrations but lower plasma insulin. During exercise, blood glucose increased 60% in T rats but decreased 20% in C rats. Plasma glucagon and insulin concentrations did not change in T rats but plasma glucagon increased and insulin decreased markedly in C rats. Plasma epinephrine (90 min: range, 0.78-2.96 ng-ml-1, (T) vs. 4.42-15.67 (C)) and norepinephrine (90 min: 0.70-2.22 (T) vs. 2.50-6.10 (C)) were lower in T than in C rats. Hepatic glycogen decreased substantially and, as with muscle glycogen, the decrease was parallel in T and C rats. The plasma concentrations of free fatty acids were higher but lactate and alanine lower in T than in C rats. In trained rats the hormonal response to exercise is blunted partly due to higher glucose concentrations. In these rats adipose tissue sensitivity to catecholamines is increased, and changes in glucagon and insulin concentrations are not necessary for increased lipolysis and hepatic glycogen depletion during exercise.
AB - Male rats (120 g) either were subjected to a 12-wk physical training program (T rats) or were sedentary controls (C rats). Subsequently the rats were killed at rest or after a 45- or 90-min forced swim. At rest, T rats had higher liver and muscle glycogen concentrations but lower plasma insulin. During exercise, blood glucose increased 60% in T rats but decreased 20% in C rats. Plasma glucagon and insulin concentrations did not change in T rats but plasma glucagon increased and insulin decreased markedly in C rats. Plasma epinephrine (90 min: range, 0.78-2.96 ng-ml-1, (T) vs. 4.42-15.67 (C)) and norepinephrine (90 min: 0.70-2.22 (T) vs. 2.50-6.10 (C)) were lower in T than in C rats. Hepatic glycogen decreased substantially and, as with muscle glycogen, the decrease was parallel in T and C rats. The plasma concentrations of free fatty acids were higher but lactate and alanine lower in T than in C rats. In trained rats the hormonal response to exercise is blunted partly due to higher glucose concentrations. In these rats adipose tissue sensitivity to catecholamines is increased, and changes in glucagon and insulin concentrations are not necessary for increased lipolysis and hepatic glycogen depletion during exercise.
KW - Animals
KW - Blood Glucose
KW - Catecholamines
KW - Glucagon
KW - Glycogen
KW - Insulin
KW - Lipid Mobilization
KW - Liver Glycogen
KW - Male
KW - Muscles
KW - Physical Conditioning, Animal
KW - Physical Exertion
KW - Rats
M3 - Journal article
C2 - 606699
VL - 43
SP - 953
EP - 958
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -
ID: 154761148