title: A reproducible procedure for measuring sodium transport in cultured human fibroblasts from normal and obese donors.
abstract: Studies on erythrocyte sodium pump activity in obesity have yielded conflicting results probably because the erythrocyte is an atypical cell, and it may not reflect ATPase activity of other cells in the body. This study was undertaken to establish a reproducible procedure to measure sodium transport in human diploid fibroblasts, and apply this method to explore any differences in the cells from obese and nonobese humans. Cell cultures were established from 12 nonobese (body mass index (BMI) = wt in kg/height in m2 (Khosla and Lowe, Br J Prev Soc Med 1967; 21: 122-128); less than 27 kg/m2) and 10 obese (BMI) greater than 35 kg/m2) subjects. Triplicate measurements of sodium efflux rate constant were made with and without ouabain (1 mmol/l) to determine the total, active (ouabain-sensitive) and passive (ouabain-insensitive) components. Reproducible results were obtained as suggested by a coefficient of variation (CV) of less 10% on successive experiments on the same cell-line, and 11 and 15% of the active sodium efflux rate constant measured in fibroblasts from nonobese and obese subjects, respectively. The active sodium efflux rate constant in fibroblasts from nonobese (0.202 +/- 0.023 (SD)) was not significantly different from that obtained in the cells from obese subjects (0.21 +/- 0.030; p greater than 0.10). These results suggest that there is no intrinsic differences in basal sodium pump activity in fibroblasts related to obesity.
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D001693:Biological Transport, Active / Q000187:drug effects; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009765:Obesity / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*
chemical_list: D010042:Ouabain; D012964:Sodium