Changes in serum proteins, viscosity, and protein-bound carbohydrates during prolonged bedrest

Studies were carried out on eight young males before, during and after 24 or more weeks bedrest. Measurements of serum viscosity, total serum protein, serum electrophoretic components, total serum solids, serum protein-bound carbohydrate, and plasma volume were carried out. A loss of plasma volume occurred early in bedrest which produced an increase in total serum protein level. Despite continuing reduced plasma volume during bedrest, the elevated serum protein level returned toward its pre-bedrest concentration with stabilization of the levels of all electrophoretic components at values very near those present before bedrest. Serum viscosity changes paralleled total serum protein values. Increase in total serum solids was measured and found to be greater than the rise in total serum protein. The excess total serum solid was nondialyzable and had little effect on viscosity. Increase in protein-bound hexose and fucose level were observed during bedrest which persisted during early reambulation. The proportionate fucose increase was greater than hexose despite stability of the gamma globulin fraction with which the majority of serum protein-bound fucose is normally associated, but no change in fucose content of haptoglobin, alpha2-macroglobulin, or alpha1-acid glycoprotein was detected in two subjects on whom sufficient material was present to allow study.