Coproporphyrin excretion in healthy newborn babies

The urinary and fecal coproporphyrins (CP) undergo significant changes in cholestatic diseases of both adults and infants and their determination may provide a diagnostic tool. Little is known about CP excretion in the first days of life. The authors have studied the daily urinary and fecal excretion of CP as well as the I and III isomer distribution in 10 healthy newborn babies from 1 to 10 days old. CP were determined by the solvent partition method and the isomer distribution by thin-layer chromatographic technique. Preliminary studies on urinary porphyrin pattern were performed using a personal high-performance liquid chromatographic method. CP excretion was almost 10 times higher on the 1st day than on the 10th, when expressed by adult standards. The isomer I accounted for almost 80% of the total amount on the first days, whereas at the end of the study, both the CP total amount and isomer distribution overlapped the infant and adult pattern. The authors propose a personal interpretation based on a possible transient enzymatic defect in the metabolic chain of heme synthesis.