EFFECTS OF ACUTE, SUBMAXIMAL EXERCISE ON VITAMIN-B-6 METABOLISM IN THE RAT

The effect of acute exercise on vitamin B-6 metabolism was assessed in Wistar rats (n=40) submitted to forced-swimming by measuring B-6 vita mers (Pyridoxal 5'-phosphate, PLP; pyridoxal, FL; pyridoxamine 5'-phos phate, PMP; pyridoxamine, PM; pyridoxine, PN) and pyridoxic acid (4-PA ) by a reverse-phase liquid chromatography method in plasma, gastrocne mius muscle, liver, brain, heart, kidneys, and adrenals at rest (n=8) and after swimming for 1.0 h (n=8), 1.5 h (n=8), 2.0 h (n=8), and 2.5 h (n=8). Results showed a significant increase in plasma total vitamin B-6 (PLP + PL + PM + PN), PLP and 4-PA levels in the exercised animal s vs. control animals. Mean PLP muscle levels (nmol/g) increased signi ficantly after 1.5 and 2.5 h of swimming. Liver PLP, FL, PM and total vitamin B-6 also increased significantly in the exercised animals. Con centrations of B-6 compounds in heart, brain, kidneys, and adrenals we re not affected. Vitamer tissue content was also expressed as total am ount (nmol per organ) since liver and muscle weights changed significa ntly after exercise. PLP, PMP and total vitamin B-6 increased in muscl e while PLP tended to decrease in liver. Our results indicated that ac ute exercise induced changes in vitamin B-6 metabolism including a ret entive capacity and temporary deposition of vitamin B-6 stores in skel etal muscle. Further studies are needed to delineate the mechanisms in volved in the regulation of vitamin B-6 distribution, transport, and s torage during exercise.