Abstract des Autors

Urine samples were collected from seven healthy male students 1 h before (control fraction) and 5-15 min (5-15 min fraction), 1 h (1-h fraction) and 3 h (3-h fraction) after running 3 km at a perceived exertion equal to approximately 15-17 Borg's scale. Venous blood was also collected from the subjects 1 h before and 1 h after the run. Urine was studied by measuring protein excretion, patterns of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of proteins, total alkaline phosphatase (ALP) excretion, intestinal alkaline phosphatase (IAP) excretion and ALP isozyme analysis by PAGE. Serum ALP was studied by measuring the total ALP activity and isozyme analysis by PAGE. The following results were observed: firstly, an increase was seen in the excretion of total protein, total ALP and IAP after the exercise. Statistical significance was seen in the first two of these parameters; secondly, albumin was the only detectable protein band in the control, 5-15 min and 3-h fraction by SDS-PAGE; thirdly, no significant changes were seen in total ALP activity and ALP isozymes in the serum; and fourthly, three to five ALP bands (bands 1, 2, 3, 4 and 5, from the cathodal side) were detected in the zymograms of urinary ALP. Bands 1-3 were high molecular mass ALP. Bands 4 and 5 were intestine-like and liver-like ALP, respectively. An increase of ALP activity of high molecular mass ALP and/or decrease of that of band 5 or appearance of band 4 were seen in the 1-h fraction, in comparison to the control fraction. We postulate that high molecular mass ALP were formed in the kidney by a combination of band 5 ALP and substance(s) induced by exercise. It is suggested from these results that urinary ALP isozymes are important elements in the investigation of the effects of exercise.