[Effect of body position on substrates, enzymes and electrolytes in the serum of healthy subjects].

32 healthy persons, 12 men and 20 women, 19 to 48 years of age, were examined in the three positions--recumbent, sitting and erect. Blood was taken by venepuncture after 15 minutes stay in the position. The analyses were carried out with the discrete analyzer "PA-1000", flame photometer, chlorine titrator "Radiometer" and osmometer "Knauer". The statistical assessment was performed by the pair analysis. The changing of the body position from recumbent to sitting and to erect leads to a significant increase of the concentrations of the total protein and albumin which cannot pass through the capillary endothelial barrier following the changes in the hydrostatic and filtration pressure. The capillary endothelial barrier is permeable for the low-molecular compounds whose concentrations change insignificantly. Cholesterol and triglycerides are an exception since they are bound to nonfilterable lipoprotein complexes. Reliable increase of creatinine is found only in the women examined. Calcium which in the serum is protein-bound also increases significantly. A significant increase is found also of the activity of the enzymes creatine kinase, alkaline phosphatase and gamma GTP. The changes of the activity of the enzymes AsAT, AlAT, LDH and hydroxybutyrate dehydrogenase are insignificant.