Studies in congenital porphyria. 3. The incorporation of 15N into the haem and glycine of haemoglobin

Abstract

N15-labelled glycine was fed on 2 separate occasions to a patient suffering from congenital porphyria. Changes of isotope content of the circulating haem indicated marked hemolysis during the 1st expt. and slight hemolysis during the 2d. These findings are supported by hematological data. Isotope contents were estimated in glycine isolated from the 2 globin samples. The results suggest that globin synthesis precedes that of haem, and that all 4 N atoms of protoporphyrin are derived from that of glycine. The "urobilinogen" excretion was raised above normal values, but not to levels anticipated on the basis of the isotope results. It is suggested that in congenital porphyria the excessive excretion of porphyrin of type I is associated with a disturbance of blood formation leading to increased breakdown of haem in the bone marrow and in the circulating blood.