Showing papers by "Rosalyn S. Yalow published in 1956"

Effect of X-Rays on Trace-Labeled I131-Insulin and Its Relevance to Biologic Studies with I131-Labeled Proteins1

Abstract: In vivo metabolic studies in man and animals have revealed that the major fraction of insulin-I131 is degraded with a half-time of the order of forty to sixty minutes or less following its intravenous administration (1). However, a smaller fraction, the magnitude of which varies with different lots of radioiodinated insulin, is removed from the blood stream at a much slower rate, with a half-time of six to twenty-four hours. It has also been shown by paper electrophoresis and paper chromatography that the slowly degraded moiety is bound to the serum proteins in contrast to the rapidly degraded fraction which is free of such association. Appraisal of the factors influencing the relative amounts of rapidly and slowly degraded fractions led to the conclusion that the serum protein-bound components represent alterations of the native insulin and to the suspicion that these alterations are manifestations of radiation damage to the hormone. The present study shows that similar changes can be produced by externa...