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Erythropoietic protoporphyria and lead intoxication: the molecular basis for difference in cutaneous photosensitivity. I. Different rates of disappearance of protoporphyrin from the erythrocytes, both in vivo and in vitro.
J Clin Invest. 1975 Dec; 56(6):1519-27.JCI

Abstract

In lead intoxication photosensitivity is usually absent, despite concentrations of protoporphyrin in the erythrocytes equal to or greater than in erythropoietic protoporphyria. Profound differences in the distribution of protoporphyrin in aging erythrocytes were demonstrated by age-dependent fractionation of cells on discontinuous density gradients. In erythropoietic protoporphyria the concentration of protoporphyrin declined extremely rapidly with erythrocyte age; the bulk of the protoporphyrin was lost in less than 3 days and the concentration of fluorescent erythrocytes in the gradient paralleled the decline of protoporphyrin. In lead intoxication the protoporphyrin concentration declined only slightly with cell aging and erythrocytes of all ages fluoresced. In the bone marrow from a patient with erythropoietic protoporphyria all reticulocytes, but only occasional late normoblasts, fluoresced, suggesting a single population. Sterile incubation in plasma (pH 7.5) demonstrated rapid diffusion of protoporphyrin from the erythrocytes in erythropoietic protoporphyria, but not in lead intoxication. Plasma protoporphyrin was elevated in erythropoietic protoporphyria, but not in lead intoxication. Estimates of the daily loss of protoporphyrin from erythropoietic tissue in erythropoietic proporphyria suggested an order of magnitude similar to the total blood protoporphyrin. Therefore, it is not necessary to postulate a preponderant extraerythropoietic source to explain the amount of fecal excretion. A significant amount of the diffused protoporphyrin probably reaches the skin with resulting photosensitivity. In contrast, in lead intoxication protoporphyrin remains within the erythrocyte throughout its life span ; there is no diffusion into the plasma and hence no photosensitivity.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1202082

Citation

Piomelli, S, et al. "Erythropoietic Protoporphyria and Lead Intoxication: the Molecular Basis for Difference in Cutaneous Photosensitivity. I. Different Rates of Disappearance of Protoporphyrin From the Erythrocytes, Both in Vivo and in Vitro." The Journal of Clinical Investigation, vol. 56, no. 6, 1975, pp. 1519-27.
Piomelli S, Lamola AA, Poh-Fitzpatrick MF, et al. Erythropoietic protoporphyria and lead intoxication: the molecular basis for difference in cutaneous photosensitivity. I. Different rates of disappearance of protoporphyrin from the erythrocytes, both in vivo and in vitro. J Clin Invest. 1975;56(6):1519-27.
Piomelli, S., Lamola, A. A., Poh-Fitzpatrick, M. F., Seaman, C., & Harber, L. C. (1975). Erythropoietic protoporphyria and lead intoxication: the molecular basis for difference in cutaneous photosensitivity. I. Different rates of disappearance of protoporphyrin from the erythrocytes, both in vivo and in vitro. The Journal of Clinical Investigation, 56(6), 1519-27.
Piomelli S, et al. Erythropoietic Protoporphyria and Lead Intoxication: the Molecular Basis for Difference in Cutaneous Photosensitivity. I. Different Rates of Disappearance of Protoporphyrin From the Erythrocytes, Both in Vivo and in Vitro. J Clin Invest. 1975;56(6):1519-27. PubMed PMID: 1202082.
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TY - JOUR T1 - Erythropoietic protoporphyria and lead intoxication: the molecular basis for difference in cutaneous photosensitivity. I. Different rates of disappearance of protoporphyrin from the erythrocytes, both in vivo and in vitro. AU - Piomelli,S, AU - Lamola,A A, AU - Poh-Fitzpatrick,M F, AU - Seaman,C, AU - Harber,L C, PY - 1975/12/1/pubmed PY - 1975/12/1/medline PY - 1975/12/1/entrez SP - 1519 EP - 27 JF - The Journal of clinical investigation JO - J Clin Invest VL - 56 IS - 6 N2 - In lead intoxication photosensitivity is usually absent, despite concentrations of protoporphyrin in the erythrocytes equal to or greater than in erythropoietic protoporphyria. Profound differences in the distribution of protoporphyrin in aging erythrocytes were demonstrated by age-dependent fractionation of cells on discontinuous density gradients. In erythropoietic protoporphyria the concentration of protoporphyrin declined extremely rapidly with erythrocyte age; the bulk of the protoporphyrin was lost in less than 3 days and the concentration of fluorescent erythrocytes in the gradient paralleled the decline of protoporphyrin. In lead intoxication the protoporphyrin concentration declined only slightly with cell aging and erythrocytes of all ages fluoresced. In the bone marrow from a patient with erythropoietic protoporphyria all reticulocytes, but only occasional late normoblasts, fluoresced, suggesting a single population. Sterile incubation in plasma (pH 7.5) demonstrated rapid diffusion of protoporphyrin from the erythrocytes in erythropoietic protoporphyria, but not in lead intoxication. Plasma protoporphyrin was elevated in erythropoietic protoporphyria, but not in lead intoxication. Estimates of the daily loss of protoporphyrin from erythropoietic tissue in erythropoietic proporphyria suggested an order of magnitude similar to the total blood protoporphyrin. Therefore, it is not necessary to postulate a preponderant extraerythropoietic source to explain the amount of fecal excretion. A significant amount of the diffused protoporphyrin probably reaches the skin with resulting photosensitivity. In contrast, in lead intoxication protoporphyrin remains within the erythrocyte throughout its life span ; there is no diffusion into the plasma and hence no photosensitivity. SN - 0021-9738 UR - https://www.unboundmedicine.com/medline/citation/1202082/Erythropoietic_protoporphyria_and_lead_intoxication:_the_molecular_basis_for_difference_in_cutaneous_photosensitivity__I__Different_rates_of_disappearance_of_protoporphyrin_from_the_erythrocytes_both_in_vivo_and_in_vitro_ L2 - https://doi.org/10.1172/JCI108233 DB - PRIME DP - Unbound Medicine ER -