On the Specific Dynamic Action of Protein

Abstract

In conjunction with data on the efficiency of the process of renal excretion, analyses of the data bearing upon the relation of the increase in metabolism following the ingestion of protein or amino acids reveals: A close correlation between the specific dynamic action of proteins or of amino acids and the increase, over the basal level of excretion, in the urinary N; that neither the direct experimental evidence nor the considerations of the energy relations support the view that the specific dynamic action of protein is necessarily due to the conversion of the deaminized fractions into glucose. The values of the specific dynamic action of amino acids and of proteins indicate that 25-60% is due to the work imposed upon the kidney. The remainder of the specific dynamic action of protein or amino acids is due to the metabolism of the N and C, though it is not possible, from the evidence, to estimate the proportion for which each is responsible. The hypothesis that the specific dynamic action of protein is due to at least two distinct processes, which do not proceed at similar rates, provides an explanation for some hitherto anomalous phenomena in the specific dynamic action of protein.