THE EFFECT OF INSULIN ANTISERUM ON THE INSULIN ACTIVITY OF SERUM AND PROTEIN FRACTIONS OF SERUM

Abstract

SUMMARY: The uptake of glucose by isolated rat diaphragm is increased in vitro by serum from normal oxen and diabetic patients treated with ox insulin; by slower moving albumin, β- and γ-globulin fractions of serum from normal oxen; by slower moving albumin, α₂-, β- and γ-globulin fractions of serum from treated diabetics (prepared by zone electrophoresis on columns of treated cellulose). More rapidly moving albumins from both types of serum did not stimulate glucose uptake. The effect of serum or protein fractions of serum was absent or markedly reduced in the presence of antiserum to ox insulin prepared in guinea-pigs. It is concluded that the stimulating effect of serum and protein fractions of serum on uptake of glucose by diaphragm is due to circulating insulin. The effect of insulin on uptake of glucose by diaphragm is shown to be potentiated by the presence of corticotrophin, prolactin, normal guinea-pig serum and an albumin preparation from the serum of hypophysectomized rats. The significance of these results in relation to the detection and assay of insulin in blood with isolated diaphragm and to the transport of insulin in blood is discussed.