Hypoproteinemia may follow excessive loss or deprivation of protein. Experimental hypoproteinemia has been produced by plasmapheresis and with diets low in protein. In man, hypoproteinemia is encountered after continued loss of protein in urine or during periods of dietary restriction of protein. Many investigators believe that the hypoproteinemia is entirely due to this loss of protein. However, in a recent discussion of the problem, Bloomfield1 suggested: "Part at least of the difficulty which leads to the lowering of the blood-proteins is an impairment of the blood-regenerating mechanism; lack and loss undoubtedly contribute an added burden which on occasion may be insuperable, but lack and loss clearly fail to explain the whole problem."
In the present investigation, control and partially nephrectomized rats fed diets containing varying amounts of dried extracted beef muscle were used in studying the relation between the plasma protein content and the amount of protein ingested and excreted.