Changes in haptoglobin and other plasma proteins of rats during exposure to pure oxygen at 760 torr

: Changes in plasma haptoglobin, total protein, hematocrit, and hemoglobin content of blood were studied in rats at various times during a 7-d exposure to oxygen at 760 torr. Plasma haptoglobin and other plasma proteins were fractionated and quantitatively evaluated for a 3-d exposure period. Total protein and haptoglobin were depressed after 7 d of exposure. Significant changes were not noted before this time. With a 3-d exposure, for which plasma proteins were fractionated, fibrinogen showed a considerable increase whereas albumin, gamma globulins, and the beta 1 globulin fraction decreased significantly. Individual variations in albumin and haptoglobin were correlated inversely to the hematocrit. These variations indicate that the altered composition of the plasma protein is due, in part, to a variable loss of the various plasma protein fractions as a result of increased vascular permeability.