Clearance of Blood Radioiodide by Transplantable Tumors of the Thyroid Gland in the Unanesthetized Rat

Abstract

Measurements were made of the clearance of blood radioiodide by transplantable tumors of the thyroid gland in the Fischer rat. In two lines the clearance was proportional to tumor mass. Clearance by the thyroid gland was relatively unaffected by tumors of line 1-2. Clearance by the thyroid gland was depressed to that in hypophy-sectomized rats by tumors of another line (1-1C) when the total tumor clearance was greater than twice the thyroid clearance. The clearance was of the order of 0.5 ml blood per g tumor per minute for tumors of some lines and approximately 0.08 ml blood per g tumor per minute for others. This indicates that the volume flow of blood in some tumors approximates that of the more actively perfused organs.