Comparison of amino acid profiles between rats subjected to forced running and voluntary running exercises

Abstract

It has been suspected that in comparison with glucose or fatty acids, the levels of amino acids may readily change with different forms of exercise. In the present study, we measured the concentrations of amino acids, glucose, triglycerides, total protein and total cholesterol in the blood and/or cerebrospinal fluid (CSF) of rats subjected to forced running exercise on a treadmill, and voluntary running exercise using a wheel, with a constant running distance of 440 m. Rats that performed no running and rats subjected to immobilization stress were used as controls. We observed a few significant changes in the levels of plasma glucose, triglycerides, total protein and total cholesterol in all groups. Whereas, plasma amino acid levels were significantly changed by exercise and stress, especially during the light period. The plasma levels of many amino acids were specifically increased by forced running; some were decreased by immobilization stress. Few amino acids showed similar changes in their levels as a result of voluntary running. In addition, there was a significant difference in the degree of amino acid imbalance between blood and CSF. These results provide the first information on changes in levels of amino acids in plasma and CSF resulting from forced and voluntary exercises.

Fig. 1.

Concentrations of blood glucose (mg/dl; A, E), triglycerides (mg/dl; B, F), total protein (g/dl; C, G) and total cholesterol (mg/dl; D, H) were measured after each experimental treatment in the light (n=5–8) and dark (n=5–7) phases. The data represent the mean ± standard error of the mean (SEM). C, control (white bar); T, treadmill running (black bar); W, wheel running (gray bar); I, immobilization (diagonal bar).

Fig. 2.

Alterations in plasma amino acid concentrations after each experimental treatment in the light (A-C) and dark (D-F) phases. The concentrations of each amino acid are shown as a percentage ratio relative to the concentrations in the control group (n=5–13). A, D: Results for the treadmill-running group (red lines), B, E: wheel-running group (green lines), C, F: immobilization group (yellow lines) and control group (black lines). Amino acids indicated in red showed significant differences vs. the control group (P<0.05).

Fig. 3.

Alterations in CSF amino acid concentrations after each experimental treatment in the light (A-C) and dark (D-F) phases. The concentrations of each amino acid are shown as a percentage ratio relative to the concentrations in the sedentary control group (n=4–13). A, D: Results for the treadmill-running group (red lines), B, E: wheel-running group (green lines), C, F: immobilization group (yellow lines) and control group (black lines). Amino acids indicated in red showed significant differences vs. the control group (P<0.05). Pro, Trp, Cys, Asp and Glu were not detectable.