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Badminton MN, Anderson KE, Deybach JC, Harper P, Sandberg S, Elder GH. From chemistry to genomics: A concise history of the porphyrias. Liver Int 2024. [PMID: 38767598 DOI: 10.1111/liv.15960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/15/2024] [Accepted: 04/18/2024] [Indexed: 05/22/2024]
Abstract
We describe developments in understanding of the porphyrias associated with each step in the haem biosynthesis pathway and the role of individuals whose contributions led to major advances over the past 150 years. The first case of erythropoietic porphyria was reported in 1870, and the first with acute porphyria in 1889. Photosensitisation by porphyrin was confirmed by Meyer-Betz, who self-injected haematoporphyrin. Günther classified porphyrias into haematoporphyria acuta, acuta toxica, congenita and chronica. This was revised by Waldenström into porphyria congenita, acuta and cutanea tarda, with the latter describing those with late-onset skin lesions. Waldenström was the first to recognise porphobilinogen's association with acute porphyria, although its structure was not solved until 1953. Hans Fischer was awarded the Nobel prize in 1930 for solving the structure of porphyrins and the synthesis of haemin. After 1945, research by several groups elucidated the pathway of haem biosynthesis and its negative feedback regulation by haem. By 1961, following the work of Watson, Schmid, Rimington, Goldberg, Dean, Magnus and others, aided by the availability of modern techniques of porphyrin separation, six of the porphyrias were identified and classified as erythropoietic or hepatic. The seventh, 5-aminolaevulinate dehydratase deficiency porphyria, was described by Doss in 1979. The discovery of increased hepatic 5-aminolaevulinate synthase activity in acute porphyria led to development of haematin as a treatment for acute attacks. By 2000, all the haem biosynthesis genes were cloned, sequenced and assigned to chromosomes and disease-specific mutations identified in all inherited porphyrias. These advances have allowed definitive family studies and development of new treatments.
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Affiliation(s)
| | - Karl E Anderson
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Jean-Charles Deybach
- French Porphyria Reference Center (CRMR Porphyries France), University Paris, Paris, France
| | - Pauline Harper
- Department of Medical Biochemistry and Biophysics, Centre for inherited Metabolic Diseases, Porphyria Centre Sweden, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Sverre Sandberg
- Department of Medical Biochemistry and Biophysics, Centre for inherited Metabolic Diseases, Porphyria Centre Sweden, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Department of Medical Biochemistry and Pharmacology, Norwegian Porphyria Centre, Haukeland University Hospital, Bergen, Norway
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway
- Institute of Public Health and Primary Health Care, University of Bergen, Bergen, Norway
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Ventura P, Ricci A. Givosiran for the treatment of acute hepatic porphyria. Expert Rev Clin Pharmacol 2022; 15:383-393. [DOI: 10.1080/17512433.2022.2075848] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Paolo Ventura
- Department of Surgical and Medical Sciences for Children and Adults, Internal Medicine Unit, University of Modena and Reggio Emilia, Modena, Italy
| | - Andrea Ricci
- Department of Surgical and Medical Sciences for Children and Adults, Internal Medicine Unit, University of Modena and Reggio Emilia, Modena, Italy
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3
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Stölzel U, Schuppan D. [New therapeutic option for acute hepatic porphyrias]. Dtsch Med Wochenschr 2021; 146:955-958. [PMID: 34344029 DOI: 10.1055/a-1282-1156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Givosiran is a small synthetic double-stranded siRNA (small interfering RNA) conjugated with N-acetyl-galactosamine (GalNAc) for specific hepatocyte targeting via the asialoglycoprotein receptor. A prospective randomized multicenter study (Envision) demonstrated the clinical efficacy of monthly subcutaneous injection of Givosiran for the prevention of attacks of acute hepatic porphyria (AHP). This leads to highly selective transcriptional inhibition of the key hepatic enzyme, aminolaevulinate synthase 1, that is overexpressed in AHP. The success of the Envision study has led to the approval of Givosiran in the US and Europe for the treatment of severe AHP. This innovative guided siRNA therapy has opened up the possibility to selectively inhibit the expression of any hepatocyte gene whose overexpression that causes pathology, which can be considered a milestone development in hepatology. However, currently this treatment with givosiran is very costly. Moreover, since some patients experience worsening of kidney function and elevated aminotransferases, monthly monitoring of these parameters is necessary in the first half year of treatment.
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Affiliation(s)
| | - Detlef Schuppan
- Institut für Translationale Immunologie, Zentrum für Zöliakie, Dünndarmerkrankungen und Autoimmunität, Johannes-Gutenberg-Universität, Mainz
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4
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Eguchi A, Fukunaga S, Ogata K, Kushida M, Asano H, Cohen SM, Sukata T. Chimeric Mouse With Humanized Liver Is an Appropriate Animal Model to Investigate Mode of Action for Porphyria-Mediated Hepatocytotoxicity. Toxicol Pathol 2021; 49:1243-1254. [PMID: 34238059 PMCID: PMC8521358 DOI: 10.1177/01926233211027474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Porphyrinogenic compounds are known to induce porphyria-mediated hepatocellular injury and subsequent regenerative proliferation in rodents, ultimately leading to hepatocellular tumor induction. However, an appropriate in vivo experimental model to evaluate an effect of porphyrinogenic compounds on human liver has not been fully established. Recently, the chimeric mouse with humanized liver (PXB mice) became widely used as a humanized model in which human hepatocytes are transplanted. In the present study, we examined the utility of PXB mice as an in vivo experimental model to evaluate the key events of the porphyria-mediated cytotoxicity mode of action (MOA) in humans. The treatment of PXB mice with 5-aminolevulinic acid, a representative porphyrinogenic compound, for 28 days caused protoporphyrin IX accumulation, followed by hepatocyte necrosis, increased mitosis, and an increase in replicative DNA synthesis in human hepatocytes, indicative of cellular injury and regenerative proliferation, similar to findings in patients with porphyria or experimental porphyria models and corresponding to the key events of the MOA for porphyria-mediated hepatocellular carcinogenesis. We conclude that the PXB mouse is a useful model to evaluate the key events of the porphyria-mediated cytotoxicity MOA in humans and suggest the utility of PXB mice for clarifying the human relevancy of findings in mice.
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Affiliation(s)
- Ayumi Eguchi
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
| | - Satoki Fukunaga
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
| | - Keiko Ogata
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
| | - Masahiko Kushida
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
| | - Hiroyuki Asano
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Tokuo Sukata
- Environmental Health Science Laboratory, Sumitomo Chemical Co, Ltd, Osaka, Japan
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5
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Abstract
Porphyrien werden durch Enzymdefekte der Hämbiosynthese hervorgerufen und anhand spezifischer biochemischer Muster von Porphyrinen und deren Vorläufern in Urin, Stuhl und Blut diagnostiziert. Das jeweilige Muster der akkumulierten Porphyrine, Vorläufer und Derivate ist verbunden mit der klinischen Ausprägung, die abdominale, neurologische, psychiatrische, endokrine, kardiovaskuläre Symptome, Leberschaden und/oder Lichtempfindlichkeit der Haut umfassen kann. Klinisch werden akute und nichtakute Porphyrien unterschieden. Bei symptomatischen (klinisch aktiven), akuten hepatischen Porphyrien – hierzu gehören akute intermittierende Porphyrie, Porphyria variegata, hereditäre Koproporphyrie und Doss-Porphyrie – kommt es aufgrund einer Regulationsstörung zur Kumulation der Porphyrinvorläufer 5‑Aminolävulinsäure und Porphobilinogen. Bei den nichtakuten Formen – u. a. Porphyria cutanea tarda, erythropoetische und X‑chromosomale Protoporphyrie sowie kongenitale erythropoetische Porphyrie – führen akkumulierte Porphyrine zu Lichtempfindlichkeit (Fotodermatose) und mitunter auch zu schweren Leberschäden. Zur Therapie der Porphyrien stehen sowohl bewährte und sichere als auch innovative Optionen zur Verfügung.
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Affiliation(s)
- Ulrich Stölzel
- Porphyrie Zentrum, Klinikum Chemnitz gGmbH, Flemmingstr. 2, 09009, Chemnitz, Deutschland.
| | - Thomas Stauch
- Porphyrie-Speziallabor EPNET, MVZ Labor PD Dr. med. Volkmann und Kollegen GbR, Gerwigstr. 67, 76131, Karlsruhe, Deutschland
| | - Ilja Kubisch
- Porphyrie Zentrum, Klinikum Chemnitz gGmbH, Flemmingstr. 2, 09009, Chemnitz, Deutschland
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7
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Wetterberg L, Haeger-Aronsen B, Stathers G. Faecal Porphyrins as a Diagnostic Index between Acute Intermittent Porphyria and Porphyria Variegata. Scandinavian Journal of Clinical and Laboratory Investigation 2009. [DOI: 10.3109/00365516809160957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Watson CJ. Some recent advances in the problem of erythropoietic porphyria. ACTA MEDICA SCANDINAVICA. SUPPLEMENTUM 2009; 445:25-35. [PMID: 5219917 DOI: 10.1111/j.0954-6820.1966.tb02335.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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9
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Rimington C. Porphyrin and haem biosynthesis and its control. ACTA MEDICA SCANDINAVICA. SUPPLEMENTUM 2009; 445:11-24. [PMID: 5220049 DOI: 10.1111/j.0954-6820.1966.tb02334.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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10
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Raigal Martín MY, Lledó Navarro JL, Raigal Martín JM, Muriel Patino E, Pérez Pérez E, Moreno Prat M. [Acute intermittent porphyria and chronic transaminase elevation]. GASTROENTEROLOGIA Y HEPATOLOGIA 2008; 31:225-8. [PMID: 18405488 DOI: 10.1157/13117900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acute intermittent porphyria is an autosomal dominant inherited disorder resulting from a deficiency of porphobilinogen deaminase activity, the third enzyme in the heme biosynthesis pathway. This disease is uncommon, although the prevalence is higher in asymptomatic heterozygotic carriers; however, this prevalence is difficult to establish because of the absence of symptoms. Although acute intermittent porphyria is a multisystemic disease, its most common form of presentation is abdominal pain and neurological or mental symptoms, which can sometimes be due to precipitating factors such as reduced energy intake, smoking, alcohol, some drugs, and stress. Diagnosis can be made by testing urinary porphobilinogen levels, with subsequent measurement of enzyme activity and DNA testing. Treatment is based on prevention of porphyria attacks by avoiding precipitating factors and early administration of intravenous glucose or hemin therapy. We present the case of a patient diagnosed with acute intermittent porphyria based on study of chronic mild alanine aminotransferase (ALT) elevation.
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11
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Jeans JB, Savik K, Gross CR, Weimer MK, Bossenmaier IC, Pierach CA, Bloomer JR. Mortality in patients with acute intermittent porphyria requiring hospitalization: a United States case series. AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 65:269-73. [PMID: 8923933 DOI: 10.1002/(sici)1096-8628(19961111)65:4<269::aid-ajmg4>3.0.co;2-k] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Acute intermittent porphyria (AIP) is a genetic disorder in which patients may have life threatening attacks of neurologic dysfunction. This study examined the prognosis during the past 50 years of patients in the United States who required hospitalization for porphyric attacks. The cumulative survival was determined for 136 patients with AIP who were hospitalized for porphyric attacks between 1940 and 1988. Diagnosis was established on the basis of clinical symptoms, in combination with increased urinary excretion of porphobilinogen. The patient group had an average age of 32 years (range 9 to 75) at diagnosis and consisted of 43 males and 93 females. At follow-up, 19 males (44%) and 31 females (33%) were decreased. The standardized mortality ratio for the 136 patients, compared to an age-matched hypothetical population experiencing USA 1970 Census Death Rates was 3.2, with a 95% confidence interval of 2.4-4.0. Most deaths occurred during the initial porphyric attack (20% of deaths) or a subsequent attack (38% of deaths). Suicide was also common (five deaths). Comparison was made between 50 patients who were diagnosed before 1971, the year in which hematin therapy became available, and 86 patients who were diagnosed afterward. There was improved survival in the latter group, particularly after 10 years from the time of diagnosis, but this did not reach statistical significance. In conclusion, the proportionate increase in mortality due to symptomatic AIP was three-fold compared to the general population during the past 50 years. The major cause of the increased mortality was the porphyric attack itself.
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Affiliation(s)
- J B Jeans
- Watson Laboratory, University of Minnesota, Minneapolis, USA
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12
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Berlin NI. The metabolism service. Cancer Invest 1995; 13:637-45. [PMID: 7583716 DOI: 10.3109/07357909509024935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Metabolism Branch, originally the Metabolism Service, created by Mider and Zubrod largely in the image that Mider had projected, has had two leaders: Berlin (1956-1971) and Waldmann (1971-present). The original design of a comparatively small senior staff of five Senior Investigators and 10 Clinical Associates (fellows), together with an 11-bed patient care unit in close proximity to the offices and laboratories, has in essence continued to the present with a comparatively small expansion under Waldmann. This unit has served as a training ground. Among its present members and alumni there are 18 members of the Association of American Physicians (AAP) and 22 members of the American Society of Clinical Investigation (ASCI). In 1994, two of the presidents of the clinical research societies, Rosenberg of the AAP and Berzofsky of the ASCI, are from the Service's ranks. This model, some would say paradigm, for the organization and function of clinical research units could be an answer to what Ahrens has called a crisis. The Metabolism Branch had the benefit of strong leadership from the NCI, particularly Endicott, The Director in the 1960s, and Mider and Zubrod, the Scientific Directors. There can be no doubt that the Branch benefited substantially, some would say enormously, from the doctor draft of the 1950s and 1960s and from the funding of the intramural research program as an integral part of the funding of each of the National Institutes.
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Affiliation(s)
- N I Berlin
- Sylvester Comprehensive Cancer Center, University of Miami, Florida, USA
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Cable EE, Pepe JA, Karamitsios NC, Lambrecht RW, Bonkovsky HL. Differential effects of metalloporphyrins on messenger RNA levels of delta-aminolevulinate synthase and heme oxygenase. Studies in cultured chick embryo liver cells. J Clin Invest 1994; 94:649-54. [PMID: 8040318 PMCID: PMC296142 DOI: 10.1172/jci117381] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The acute porphyrias in relapse are commonly treated with intravenous heme infusion to decrease the activity of delta-aminolevulinic acid synthase, normally the rate-controlling enzyme in heme biosynthesis. The biochemical effects of heme treatment are short-lived, probably due in part to heme-mediated induction of heme oxygenase, the rate-controlling enzyme for heme degradation. In this work, selected nonheme metalloporphyrins were screened for their ability to reduce delta-aminolevulinic acid synthase mRNA and induce heme oxygenase mRNA in chick embryo liver cell cultures. Of the metalloporphyrins tested, only zinc-mesoporphyrin reduced delta-aminolevulinic acid synthase mRNA without increasing heme oxygenase mRNA. The combination of zinc-mesoporphyrin and heme, at nanomolar concentrations, decreased delta-aminolevulinic acid synthase mRNA in a dose-dependent manner. The combination of zinc-mesoporphyrin (50 nM) and heme (200 nM) decreased the half-life of the mRNA for delta-aminolevulinic acid synthase from 5.2 to 2.5 h, while a similar decrease was produced by heme (10 microM) alone (2.2 h). The ability of zinc-mesoporphyrin to supplement the reduction of delta-aminolevulinic acid synthase mRNA by heme, in a process similar to that observed with heme alone, provides a rationale for further investigation of this compound for eventual use as a supplement to heme therapy of the acute porphyrias and perhaps other conditions in which heme may be of benefit.
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Affiliation(s)
- E E Cable
- Department of Medicine, University of Massachusetts Medical Center, Worcester 01655
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Helson L, Braverman S, Mangiardi J. delta-Aminolevulinic acid effects on neuronal and glial tumor cell lines. Neurochem Res 1993; 18:1255-8. [PMID: 8272191 DOI: 10.1007/bf00975044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Acute intermittent porphyria (AIP) or precursor syndrome is a well described neuropathic clinical entity with incompletely known etiology. The most prominent biological abnormalities associated with this syndrome are elevations in serum and hepatic delta-aminolevulinic acid (ALA) and porphobilinogen (PBG). We determined the impact of ALA and PBG on human neuroblastoma and glioblastoma tumor cell survival as measured by the MTT assay. ALA proved to be cytotoxic in neuroblastoma cells, while PBG lacked cytotoxic effects. This cytotoxic effect of ALA could be enhanced by deferoxamine and diminished by heme, presumably through modulation of ALA synthesis. In conclusion, ALA excess may prove to be associated with the development of neuropathy in AIP.
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Affiliation(s)
- L Helson
- New York Medical College, Department of Medicine, Valhalla 10595
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15
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Abstract
The role of alcohol as the precipitating factor in the induction of acute attacks of acute intermittent porphyria was studied in an Indian population. Thirty-four teetotal patients with acute intermittent porphyria, in remission, were given 60 ml of 30% ethanol. Except for two patients, all had negative Watson-Schwartz tests prior to the alcohol. Within 24 hours, the Watson-Schwartz test became positive in 16 of these 32 patients (50%). In 8 out of the 34 patients (23.5%) a clinical attack was precipitated, including both patients who had a positive Watson-Schwartz test prior to the alcohol. It was concluded that alcohol does precipitate an acute attack in a significant percentage of patients of Indian origin with acute intermittent porphyria. Patients already excreting porphobilinogen are at a greater risk of developing an acute attack on alcohol ingestion. This study is the first from India and probably first of its kind to be reported from any country.
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Affiliation(s)
- H C Saksena
- Department of Medicine, S.P. Medical College, Rajasthan, India
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Marcus DL, Nadel H, Lew G, Freedman ML. Cimetidine suppresses chemically induced experimental hepatic porphyria. Am J Med Sci 1990; 300:214-7. [PMID: 2248274 DOI: 10.1097/00000441-199010000-00003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ability of cimetidine to reduce the activity of hepatic aminolevulinic acid synthase (ALA-S) was examined in allylisopropyl acetamide (AIA) treated porphyric adult rats. A dose of 20 mg cimetidine/100 gm body weight resulted in a 50% decrease in the AIA-induced hepatic ALA-S activity compared to rats treated with AIA alone. Heme oxygenase activity was decreased 25% compared to rats treated with AIA alone. The effects of AIA and cimetidine on cytochrome P-450 were not additive, suggesting competition for a common site of interaction. The results suggest that cimetidine may prove to be useful in treating porphyria in humans.
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Affiliation(s)
- D L Marcus
- Department of Medicine, NYU Medical Center, New York 10016
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Doss M, Benkmann HG, Goedde HW. delta-Aminolevulinic acid dehydrase (porphobilinogen synthase) in two families with inherited enzyme deficiency. Clin Genet 1986; 30:191-8. [PMID: 3780034 DOI: 10.1111/j.1399-0004.1986.tb00594.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The inheritance of a deficient delta-aminolevulinic acid dehydrase (ALA-D; synonym: porphobilinogen synthase; EC 4.2.1.24) was studied in blood samples of two families over three generations. The propositus in each family was a young male acute hepatic porphyria patient with an almost complete ALA-D deficiency in the homozygous state (ALA-D activity less than 2% of controls). Heterozygotes are clinically non-affected (mean ALA-D 36% of controls). The mode of transmission could be traced by enzyme activity and electrophoretic polymorphism studies. Heterozygotes are detected by the demonstration of enzyme activity in the gel. The notation D was used for the gene expressing the defective enzyme. The "phenotype" D-1 was observed in six, the "phenotype" D-2 in three of all heterozygotes studied. These results are compatible with a single normal allele in heterozygotes responsible for enzyme activity. Quantitative assays and the segregation pattern in both families suggest a 3-allele-system for the inheritance of ALA-D deficiency.
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Anderson PM, Reddy RM, Anderson KE, Desnick RJ. Characterization of the porphobilinogen deaminase deficiency in acute intermittent porphyria. Immunologic evidence for heterogeneity of the genetic defect. J Clin Invest 1981; 68:1-12. [PMID: 7251856 PMCID: PMC370766 DOI: 10.1172/jci110223] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The molecular pathology of the porphobilinogen (PBG)-deaminase deficiency in heterozygotes for acute intermittent porphyria (AIP) was investigated by means of biochemical and immunologic techniques. The stable enzyme-substrate intermediates (A, B, C, D, and E) of PBG-deaminase were separated by anion-exchange chromatography of erythrocyte lysates from heterozygotes for AIP and normal individuals. In normal lysates, the intermediates eluted in a characteristic pattern with decreasing amounts of activity (A > B > C > D > E), the combined A and B intermediates representing >75% of total recovered activity. In contrast, two different profiles were observed in lysates from heterozygotes for AIP. In most heterozygotes, the elution profile was similar to that of normal individuals, but each intermediate was reduced approximately 50%. A second profile in which the C intermediate had disproportionately higher activity than the A or B intermediates was observed in asymptomatic heterozygotes with high urinary levels of PBG (>5 mug/ml) as well as in heterozygotes during acute attacks. These findings suggested that the C intermediate (the dipyrrole-enzyme intermediate) may be rate limiting in the stepwise conversion of the monopyrrole, PBG, to the linear tetrapyrrole, hydroxymethylbilane. To investigate further the nature of the enzymatic defect in AIP, sensitive immunotitration and immunoelectrophoretic assays were developed with the aid of a rabbit anti-human PBG-deaminase IgG preparation produced against the homogeneous enzyme. Equal amounts of erythrocyte lysate activity from 32 heterozygotes for AIP from 22 unrelated families and 35 normal individuals were immunoelectrophoresed. There were no detectable differences in the amounts of cross-reactive immunologic material (CRIM) in lysates from the normal individuals and 25 heterozygotes from 21 of the 22 unrelated families with AIP. In contrast, when equal enzymatic activities were coimmunoelectrophoresed, all seven heterozygotes from one family had approximately 1.6 times the amount of CRIM compared with that detected in normal lysates. Consistent with these findings, immunotitration studies also demonstrated similar quantities of noncatalytic CRIM in lysates from this AIP family. When equal activities of the individual A, B, C, and D enzyme-substrate intermediates from normal and CRIM-positive erythrocytes were immunoelectrophoresed, increased amounts of immunoreactive protein were observed for each intermediate, B > A approximately C approximately D, from the CRIM-positive AIP variants. On the basis of these findings, it is hypothesized that the enzymatic defect in the CRIM-positive AIP family resulted from a mutation in the structural gene for PBG-deaminase which altered the catalytic as well as a substrate binding site. These studies of the enzymatic defect provide the first demonstration of genetic heterogeneity in AIP.
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Bloomer JR. Enzyme defects in the porphyrias and their relevance to the biochemical abnormalities in these disorders. J Invest Dermatol 1981; 77:102-6. [PMID: 7252240 DOI: 10.1111/1523-1747.ep12479280] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Defects in enzymes of the heme biosynthesis pathway underlie the biochemical abnormalities which occur in the porphyrias. Porphyrins and porphyrin precursors are accumulated and excreted in excessive amounts because of the enzyme defects. This is illustrated by studies in protoporphyria and variegate porphyria, disorders in which the biochemical abnormalities indicate a defect(s) in the terminal part of the heme biosynthesis pathway. The activity of heme synthease (ferrochelatase), which catalyzes the chelation of ferrous iron to protoporphyrin, is deficient in tissues of patients with protoporphyria. This causes protoporphyrin to be accumulated and excreted excessively. In variegate porphyria protoporphyrinogen oxidase, which catalyzes the oxidation of protoporphyrinogen to protoporphyrin, appears to be defective. As a result, protoporphyrinogen may be excreted in increased amounts in bile, where it is subsequently auto-oxidized to protoporphyrin. The following questions have arisen as a result of the demonstrations of enzyme defects in tissues of patients with porphyria: (1) Will different defects in the same enzyme be found among patients who fulfill the clinical and biochemical criteria for diagnosis of a specific porphyria? That is, does genetic heterogeneity exist in each of the porphyrias? (2) Why do some patients with an enzyme defect not have biochemical abnormalities? (3) Why is one type of tissue, usually the liver, the major site of expression of the biochemical abnormality, when the enzyme defect can be demonstrated in all tissues?
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Doss M, Verspohl F. The "glucose effect" in acute hepatic porphyrias and in experimental porphyria. KLINISCHE WOCHENSCHRIFT 1981; 59:727-35. [PMID: 7253546 DOI: 10.1007/bf01721260] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The "glucose effect" was investigated in human acute hepatic porphyrias (acute intermittent porphyria, variegate porphyria, coproporphyria and porphobilinogen synthase defect porphyria) and in avian liver cells. 8 patients (7 women) with acute abdominal-neurological porphyria syndrome and 3 patients (2 women) in the remission phase were treated with high carbohydrate intake (approximately 500 g/24 h), mainly in form of intravenous glucose infusions. The biochemical response with a decrease of metabolites of porphyrin biosynthesis was highly significant, accompanied by clinical improvement in 10 courses of 9 patients. Two patients with delayed detection of the disease under the condition of Landry paralysis died after temporary clinical improvement due to ventricular arrythmias in one case and septicemia in the other. The importance of early diagnosis and therapy, and omission of drugs and alcohol cannot be overemphasized. Complementary studies show the "glucose effect" in drug -mediated induction of porphyrin synthesis in liver cells grown in culture: delta-Aminolevulinic acid synthase and protoporphyrin synthesis are repressed.
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Sassa S, Kappas A. Genetic, metabolic, and biochemical aspects of the porphyrias. ADVANCES IN HUMAN GENETICS 1981; 11:121-231. [PMID: 7023204 DOI: 10.1007/978-1-4615-8303-5_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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22
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Chandrika SR, Padmanaban G. Purification, properties and synthesis of delta-aminolaevulinate dehydratase from Neurospora crassa. Biochem J 1980; 191:29-36. [PMID: 6451221 PMCID: PMC1162178 DOI: 10.1042/bj1910029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Delta-aminolaevulinate dehydratase, the second and rate-limiting enzyme of the haem-biosynthetic pathway, was purified 300-fold from induced cultures of Neurospora crassa. The native enzyme has a mol.wt. of about 350000, whereas the salt-treated enzyme after incubation at 37 degrees C for 10 min has a mol.wt. of about 232000. The mol.wt. of the subunit is about 38000. Antibodies to the purified enzyme were raised in rabbits. By using radiolabelling and immunoprecipitation techniques it was shown that addition of iron and laevulinate to iron-deficient cultures brings about a significant increase in the synthesis of the enzyme, and protoporphyrin, the penultimate end product of the pathway, represses enzyme synthesis.
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23
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Frydman RB, Frydman B. Disappearance of porphobilinogen deaminase activity in leaves before the onset of senescence. PLANT PHYSIOLOGY 1979; 63:1154-7. [PMID: 16660874 PMCID: PMC542987 DOI: 10.1104/pp.63.6.1154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The activity of porphobilinogen deaminase was measured in young and senescent or mature leaves of pepper (Capsicum annuum), and poinsettia (Euphorbia pulcherrima). Whereas high activity was found in the crude extracts of the young leaves, almost no activity was found in the extracts of senescent or mature leaves. The decrease in deaminase activity was not due to the presence of an isolatable inhibitor. By purifying the crude enzyme extracts from leaves of different ages on DEAE-cellulose columns it was shown that the decrease in deaminase activity was due to a real decrease in the amount of enzyme. Fruiting also decreased porphobilinogen deaminase activity. Several kinetic constants of the C. annuum deaminase were determined.
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Affiliation(s)
- R B Frydman
- Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Junin 956, Buenos Aires, Argentina
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26
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Graham DJ, Brodie MJ, McColl KE, Moore MR, Goldberg A. Quantitation of 3-ethyl-5-hydroxy-4,5-dimethyl-delta 3-pyrrolin-2-one in the urine of patients with acute intermittent porphyria. Eur J Clin Invest 1979; 9:49-53. [PMID: 110600 DOI: 10.1111/j.1365-2362.1979.tb01666.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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27
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Leonhardt KF, Tiepermann RV, Doss M. [Diagnosis of acute intermittent porphyria. Results of neurological, biochemical and genetic studies]. J Neurol 1978; 218:107-23. [PMID: 78972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurological and biochemical studies have been performed on four AIP families with 21 members. Five patients suffered from manifested AIP (Uroporphyrinogen Synthase defect and characteristic urine findings); among their relatives five persons with latent AIP were detected and eight carriers of the genetic-enzymic defect (Uroporphyrinogen Synthase defect). Internal and neurological symptoms could be interpreted as a panneuropathy. Acute and chronical polyneuropathies could be observed as well as myelopathies and cerebral co-reactions. A frequent symptom dominating the crisis and the latent state of AIP were etiologically abscure 'myalgias.' The character of the course of AIP is various and dubious: beyond the 'classical' courses with its intermittent porphyric crises we observed one case which was characterized by a permanent crisis and a second case marked by a chronical, slow progredient course without any porphyric attacks.
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28
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Zur Diagnostik der akuten intermittierenden Porphyrie: Ergebnisse neurologischer, biochemischer und genetischer Untersuchungen. J Neurol 1978. [DOI: 10.1007/bf02402171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Brodie MJ, Moore MR, Thompson GG, Goldbrrg A, Holti G. Haem biosynthesis in peripheral blood in erythropoietic protoporphyria. Clin Exp Dermatol 1977; 2:381-8. [PMID: 603977 DOI: 10.1111/j.1365-2230.1977.tb01579.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Tomaro ML, Frydman RB. Porphobilinogen oxygenase induction by 2-allyl-2-isopropylacetamide treatment. FEBS Lett 1977; 84:29-32. [PMID: 590523 DOI: 10.1016/0014-5793(77)81050-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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32
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Abstract
Evidence is presented that each of the porphyrias represents a different inborn error of metabolism in haem biosynthesis. Control of the pathway takes place by feedback repression and inhibition by haem of delta-aminolaevulinic-acid synthase. It is suggested that insituations where the activity of this enzyme is derepressed, prophobilinogen deaminase represents a secondary control step.
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33
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Abstract
Acute intermittent porphyria, variegate porphyria, and hereditary coproporphyria are hepatic porphyrias due to enzyme defects that are inherited as autosomal dominants. Porphyria cutanea tarda is considered an acquired disorder. Similar drugs or circumstances are precipitants of acute attacks in all three inherited hepatic porphyrias. The respective biochemical abnormalities are identifiable by simple, readily available laboratory tests. Management of patients with any of the inherited hepatic porphyrias is directed primarily toward prevention of attacks through avoidance of precipitants and through a diet high in carbohydrate. Therapy for porphyria cutanea tarda includes interdiction of alcohol use and repeated phlebotomy.
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34
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Becker DM, Viljoen JD, Katz J, Kramer S. Reduced ferrochelatase activity: a defect common to porphyria variegata and protoporphyria. Br J Haematol 1977; 36:171-9. [PMID: 871431 DOI: 10.1111/j.1365-2141.1977.tb00637.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Erythroid ferrochelatase activity has been studied in the normoblasts of patients with porphyria variegata and protoporphyria. Two methods were used for the investigation: one using intact cells and the other lysed cells, each measuring the amount of haem synthesized by normoblasts. In patients with porphyria variegata, ferrochelatase activity estimated by both methods was approximately 50% of the normal, and in protoporphyria the ferrochelatase activity was normal in intact normoblasts but was 20% of the normal in sonicated normoblasts (marrow lysates). It is suggested therefore that in porphyria variegata a dominantly inherited structural gene mutation results in an active ferrochelatase whereas in protoporphyria the genetic mutation results in an unstable ferrochelatase. The mechanism of the enzyme instability is not known though a number of postulates are discussed.
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Watson CJ, Pierach CA, Bossenmaier I, Cardinal R. Postulated deficiency of hepatic heme and repair by hematin infusions in the "inducible" hepatic porphyrias. Proc Natl Acad Sci U S A 1977; 74:2118-20. [PMID: 266732 PMCID: PMC431086 DOI: 10.1073/pnas.74.5.2118] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
There is compelling, indirect evidence of hepatic heme deficiency due primarily to the respective genetic errors of the three inducible hepatic porphyrias, acute intermittent porphyria, porphyria variegata, and hereditary coproporphyria. The induction is enhanced by exogenous inducers such as barbiturate, estrogens and other "porphyrogenic" chemicals and factors, including glucose deprivation. The newer knowledge of the induction of delta-aminolevulinic acid synthetase [delta-aminolevulinate synthase; succinyl--CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37] in relation to inadequate heme, and repression by heme, stimulated early trials of hematin infusions to overcome the acute relapse in the foregoing inducible porphyrias. Recently this experience has been considerably expanded, 143 infusions of hematin having been given in 22 cases. Studies of the effect on the serum concentrations of delta-aminolevulinic acid and porphobilinogen have shown a highly significant decline, often to 0, especially of delta-aminolevulinic acid. A distinct relationship to the clinical severity of the attack has been evident in the frequency and magnitude of decline of serum delta-aminolevulinic acid and porphobilinogen. This was regularly associated with objective clinical improvement.
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36
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Maxwell JD, Meyer UA. Effect of lead on hepatic delta-aminolaevulinic acid synthetase activity in the rat: a model for drug sensitivity in intermittent acute porphyria. Eur J Clin Invest 1976; 6:373-9. [PMID: 976299 DOI: 10.1111/j.1365-2362.1976.tb00531.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The hereditary hepatic porphyrias are disorders of porphyrin and haem synthesis characterized by a marked idiosyncrasy towards a variety of lipid soluble drugs. Most of these agents are inducers of the haemoprotein cytochrome P450, the terminal oxidase in drug metabolism. The primary genetic defect in intermittent acute porphyria is a partial deficiency of uroporphyrinogen I synthetase, which may result in a secondary derepression of delta-aminoaevulinic acid synthetase, the rate-limiting enzyme in the haem pathway. Analogous defects at more distant sites may explain the other hereditary hepatic porphyrias. As drug sensitivity may be related to the defect in haem synthesis, we investigated the effects of experimental partial blocks in haem synthesis produced by lead in rats. Drug effects on delta-aminolaevulinic acid synthetase, cytochrome P450, And drug metabolism were studied. Our findings indicate: a) While partial impairment of haem biosynthesis has only minor effects on delta-aminolaevulinic acid synthetase activity, it greatly enhances the sensitivity of delta-aminolaevulinic acid synthetase to induction by drugs and steroids, which when given alone, have little or no inducing effect on the enzyme. b) The experimental partial block in haem synthesis delays and impairs drug-mediated induction cytochrome P450 and drug metabolism in vitro. The findings may explain why a large number of structurally unrelated compounds with little effect on normal liver can precipitate "aucte porphyria".
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37
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Verma IC, Singh S. Perspectives in acute intermittent porphyria. Indian J Pediatr 1976; 43:204-7. [PMID: 1002227 DOI: 10.1007/bf02751598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Cox RP, King JC. Gene expression in cultured mammalian cells. INTERNATIONAL REVIEW OF CYTOLOGY 1976; 43:281-351. [PMID: 4408 DOI: 10.1016/s0074-7696(08)60071-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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40
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Effects by heme, insulin, and serum albumin on heme and protein synthesis in chick embryo liver cells cultured in a chemically defined medium, and a spectrofluorometric assay for porphyrin composition. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)40633-9] [Citation(s) in RCA: 214] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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41
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Lane SE, Gidari AS, Levere RD. Cytoplasmic receptor protein for etiochalanolone in chick embryo liver. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)40836-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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42
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Frydman RB, Tomaro ML, Frydman B, Wanschelbaum A. Porphobilinogen excretion in chemical induced porphyria: reversal by induction of porphobilinogen oxygenase. FEBS Lett 1975; 51:206-10. [PMID: 1123056 DOI: 10.1016/0014-5793(75)80888-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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43
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Die Bestimmung der Uroporphyrinogen I-Synthetase im Vollblut — eine Methode zur Diagnostik und Früherkennung der akuten intermittierenden Porphyrie. ACTA ACUST UNITED AC 1975. [DOI: 10.1007/978-3-642-85450-7_421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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44
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Roomi MW. Delta-aminolaevulinic acid synthetase. Synthesis of delta-aminolaevulinic acid pyrroles and their separation by thin-layer chromatography. J Chromatogr A 1974; 97:87-91. [PMID: 4417494 DOI: 10.1016/s0021-9673(01)97591-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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45
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Aoki Y, Urata G, Wada O, Takaku F. Measurement of delta-aminolevulinic acid synthetase activity in human erythroblasts. J Clin Invest 1974; 53:1326-34. [PMID: 4825227 PMCID: PMC302620 DOI: 10.1172/jci107680] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A new, specific, and simple method for the determination of delta-aminolevulinic acid (ALA) synthetase activity in human bone marrow cells has been developed. ALA synthetase of erythroblasts was partially purified so as to permit the use of [(14)C]succinyl-CoA as a substrate for this enzyme. In this enzyme preparation there were negligible activities of succinyl-CoA hydrolase, alpha-ketoglutarate dehydrogenase, and succinyl-CoA synthetase and there was no activity of ALA dehydrase. The ALA formed from [(14)C]succinyl-CoA has been isolated by column chromatography. Radioactivity in the eluate from the column has been proved by paper chromatography to be exclusively that of [(14)C]ALA. The entire assay can be completed within 4 h, and [(14)C]succinyl-CoA was incorporated into [(14)C]ALA on the order of several percent. Moderate to marked decreases of ALA synthetase activity have been demonstrated in the erythroblasts of all cases of sideroblastic anemia. In the cases of iron deficiency anemia, on the other hand, normal or slightly elevated activity has been obtained.
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Sassa S, Granick S, Bickers DR, Bradlow HL, Kappas A. A microassay for uroporphyrinogen I synthase, one of three abnormal enzyme activities in acute intermittent porphyria, and its application to the study of the genetics of this disease. Proc Natl Acad Sci U S A 1974; 71:732-6. [PMID: 4522787 PMCID: PMC388087 DOI: 10.1073/pnas.71.3.732] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A new spectrofluorometric assay is described for quantitating uroporphyrinogen I synthase (EC 4.3.1.8) activity in volumes of human blood as small as 2 mul. By this sensitive assay the inheritance of the enzyme's activity has been studied and the genetic defect for acute intermittent porphyria has been confirmed to be autosomal dominant in nature. There is a 3-fold range of uroporphyrinogen I synthase activity in erythrocytes in the normal population, with a mean V(max) +/- SD of 35.7 +/- 8.4 nmol of uroporphyrinogen I formed per ml of erythrocytes per hr, at 37 degrees . One-half this level of enzyme activity (18.0 +/- 5.0) is found in erythrocytes from patients with clinically manifest acute intermittent porphyria; and in erythrocytes from those of their relatives, including prepubertal children, who have the latent gene defect for the disease. The K(m) of erythrocyte enzyme of normal people is 12.3 +/- 3.9 muM, whereas the K(m) of the erythrocyte enzyme of patients with acute intermittent porphyria is 6.2 +/- 3.9 muM, as determined on whole blood lysates. Three enzymic changes have now been identified in patients with acute intermittent porphyria; a high level of delta-aminolevulinate synthase activity; a low level of uroporphyrinogen I synthase activity; and a deficiency of steroid Delta(4)-5alpha reductase activity.
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Peters HA, Cripps DJ, Reese HH. Porphyria: theories of etiology and treatment. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1974; 16:301-55. [PMID: 4606919 DOI: 10.1016/s0074-7742(08)60199-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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49
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Bradlow HL, Gillette PN, Gallagher TF, Kappas A. Studies in porphyria. II. Evidence for a deficiency of steroid delta-4-5-alpha-reductase activity in acute intermittent porphyria. J Exp Med 1973; 138:754-63. [PMID: 4270345 PMCID: PMC2180579 DOI: 10.1084/jem.138.4.754] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Patients with the genetic liver disease, acute intermittent porphyria (AIP), have a defect in the reductive transformation of steroid hormones that is manifest by the disproportionate generation of 5beta-steroid metabolites from precursor hormones. 5beta-steroid metabolites were earlier shown to be potent inducers experimentally of delta-aminolevulinate synthetase (ALAS), the mitochondrial enzyme that is rate-limiting in porphyrin synthesis, and that is found at high levels of activity in the livers of AIP patients. In this report, the basis for the defective steroid metabolism in AIP has been shown, through studies with the (14)C-labeled adrenal hormone 11beta-hydroxy-Delta(4)-androstenedione, to reside in a substantial deficiency of hepatic steroid Delta(4)-5alpha-reductase activity. This enzymic deficiency was found in all seven AIP patients studied, and ranged from 34% to as much as 70% below the mean enzyme activity characterizing normal subjects. The functional consequence of the low levels of 5alpha-reductase activity in AIP is to divert the reductive transformation of certain natural hormones from the 5alpha- to the 5beta-pathway; the latter is the metabolic route through which endogenous steroids having the potential for inducing hepatic ALAS are generated. It is not presently known whether the 5alpha-reductase deficiency in AIP is acquired in some fashion or whether it has partial genetic determinants. It seems probable, however, that this enzymatic abnormality, coupled with the dramatic increase in hormone synthesis that occurs at puberty, may be of major importance in determining clinical expression of the latent gene defect for AIP in many individuals. The 5alpha-reductases for steroid hormones are known to be localized in the endoplasmic reticulum of hepatic cells and the present findings in AIP thus represent the first demonstration that an enzymic component of these membranous structures is functionally abnormal in this hereditary liver disease.
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