The Problem of Hypoproteinemia *

The serum protein concentration has frequently been observed to be reduced in certain types of Bright's disease and in various types of malnutrition. Formerly the fundamental cause for this was attributed to either a loss of protein in the urine or a lack of protein in the diet. In 1933, in introducng studies on the effect of restriction of protein intake on the serum protein concentration of the rat, Bloomfield8 critically examined the evidence in support of the "loss and lack" theory, and concluded that such a simple concept did not fit all the facts of clinical and experimental experience. The hypothesis was advanced that some other factor, such as an impairment of or an injury to the serum protein regenerating mechanism, may be an accessory, if not the primary, factor in the production of a hypoproteinemia. More recent investigations by other workers and studies conducted in this laboratory afford further support for this hypothesis. However, in view of the controversy concerning the question, it seems profitable to review critically the evidence in support of the "loss and lack" theory and the arguments which have led investigators' 8, 38, 88,40,48 to postulate an additional factor in the production of a hypoproteinemia.