LYMPHATIC FLOW IN HUMAN SUBJECTS AS INDICATED BY THE DISAPPEARANCE OF I131-LABELED ALBUMIN FROM THE SUBCUTANEOUS TISSUE*†

Abstract

The disappearance of human serum albumin labeled with radioiodine from the subcutaneous tissue of the forearm or leg described an exponential slope and was followed by the appearance of radioactive albumin in the blood. The rate of removal of Il31-albumin from the tissues was significantly reduced in edema caused by lymphatic obstruction, but significantly increased in edema caused by venous obstruction, con- gestive heart failure of hypoproteinemia. The disappearance of Na24Cl or of Na131 from the tissues was considerably more rapid than that of I131-albumin and was not significantly altered in lymphatic edema, although it was significantly reduced in cardiac edema. Following treatment of the heart failure, the clearance of labeled protein and inorganic ions changed in opposite directions and returned to or toward normal values. These findings indicate that ll31-albumin injected into the subcutaneous tissue is removed mainly by lymphatic vessels and suggest that lymphatic flow is reduced in lymphedema but is increased in cardiac and other types of edema.