Coproporphyrin I and III excretion in bile and urine

Neil Kaplowitz; Norman Javitt; Attallah Kappas

doi:10.1172/JCI107113

^{Gastrointestinal Division, Department of Medicine, Cornell University Medical College, New York 10021}

^{The Rockefeller University, New York 10021}

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^{Gastrointestinal Division, Department of Medicine, Cornell University Medical College, New York 10021}

^{The Rockefeller University, New York 10021}

Find articles by Javitt, N. in: PubMed | Google Scholar

^{Gastrointestinal Division, Department of Medicine, Cornell University Medical College, New York 10021}

^{The Rockefeller University, New York 10021}

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Published in Volume 51, Issue 11 on November 1, 1972
J Clin Invest. 1972;51(11):2895–2899. https://doi.org/10.1172/JCI107113.
© 1972 The American Society for Clinical Investigation

Published November 1, 1972 - Version history

The excretion of coproporphyrin isomers I and III was studied in the rat. Both isomers were found to bind equally to rat plasma and liver cytosol in vitro and to disappear from plasma at equal rates after single injections in vivo. During equimolar infusions of isomers into bile fistula animals, both the I and III isomers were excreted in bile in a concentration ratio of 2:1, respectively. Pretreatment of animals with ethinylestradiol or simultaneous infusions of phenoldibromophthalein disulfonate caused a reduction in total hepatic excretion with no change in the 2:1 ratio in bile. As hepatic excretion fell, excretion of both isomers in urine rose, with an increase in the proportion of the I isomer. The findings mimic those reported to occur in man and can be explained by inhibition of a common carrier which requires a stereospecific configuration that statistically favors the hepatic transport of the symmetrical coproporphyrin I isomer.