Urinary Porphyrin Profiling

Summary

Porphyrinopathy is an umbrella term for any disorder in porphyrin metabolism. This book excerpt explains what porphyrins are and how urine testing can detect their metabolic disorders and toxic effects. Dr. Richard S. Lord, Dr. J. Alexander Bralley

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Lord RS, and Bralley JA, "Urinary Porphyrin Profiling," excerpt from Laboratory Evaluations in Functional and Integrative Medicine, 2007.

Details

Heme is required at the active sites of oxygen-binding, oxygen utilizing and oxidizing systems, hemoglobin (and myoglobin), cytochromes and mitochondrial electron carriers, respectively. Heme is a macrocyclic, iron-sequestering molecule that is synthesized in most human tissues (predominantly liver and bone marrow) by a pathway with intermediates called porphyrinogens. The final phase of metal incorporation inserts iron, cobalt or magnesium into the protoporphyrin ring to produce heme, cobalamin and, in plants, chlorophyll, respectively. These complex organometallic structures are sometimes called the pigments of life. Porphyrins are oxidized by-products that have escaped from the pathway. The spilling of porphyrins into urine or more porphyrinogens, that leads to the corresponding rise of porphyrins in urine, is called porphyrinuria. The term porphyria may be reserved for primary conditions exhibiting specific clinical symptoms caused by an inherited defect in one or more of the heme biosynthetic enzymes.