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Huss JM, Wang SI, Kasper CB. Differential glucocorticoid responses of CYP3A23 and CYP3A2 are mediated by selective binding of orphan nuclear receptors. Arch Biochem Biophys 1999; 372:321-32. [PMID: 10600171 DOI: 10.1006/abbi.1999.1496] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CYP3A2 and CYP3A23 are two cytochrome P450 genes in rat that are differentially regulated in both their constitutive activities and their responsiveness to glucocorticoids, the prototypic CYP3A inducers. CYP3A2 displays 20-25% of the response to glucocorticoids as CYP3A23 despite extensive sequence homology in their 5'-regulatory regions. Promoter deletion analyses revealed that the CYP3A2 -57 to -168 region, homologous to the CYP3A23 dexamethasone-responsive region, mediated its low level activation. When this region was analyzed by DNase I footprinting, three binding sites were shown to correspond to the functional elements described for CYP3A23: DexRE-1, DexRE-2, and Site A (J. M. Huss and C. B. Kasper (1998) J. Biol. Chem. 273: 16155-16162). The CYP3A2 DexRE-2 and Site A elements bear two mismatches each from the CYP3A23 elements but displayed similar binding patterns in footprinting and gel-shift analyses as their CYP3A23 counterparts. The region containing 3A2DexRE-1 has six mismatches and displayed unique footprinting and gel-shift patterns compared to 3A23DexRE-1. Functional assays revealed that four mismatches within the DexRE-1 and DexRE-2 elements accounted for the differential inducibility of the two isoforms. We propose that the reduced responsiveness of CYP3A2 is the result of preferential binding of COUP-TF at the CYP3A2 DexRE-1 site. In contrast, CYP3A23 DexRE-1 associates with an accessory factor(s) that acts in concert with downstream sites to mediate the strong glucocorticoid induction response observed for CYP3A23. Site A mismatches did not influence induction magnitude but were responsible for basal activity differences. Higher CYP3A23 basal activity appears to be due to an E-box in 3A23SiteA that interacts with USF1, a ubiquitous bHLH/leucine zipper transcription factor. This site is disrupted in the corresponding 3A2SiteA. Hence, 4 nucleotide mismatches within two elements account for the difference in glucocorticoid induction, and a single mismatch is responsible for the fivefold difference in the basal activities of CYP3A2 and CYP3A23.
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Affiliation(s)
- J M Huss
- Department of Oncology, Environmental Toxicology Program, McArdle Laboratory for Cancer Research, Madison, Wisconsin, 53706, USA
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Butler MP, Wang SI, Chaganti RS, Parsons R, Dalla-Favera R. Analysis of PTEN mutations and deletions in B-cell non-Hodgkin's lymphomas. Genes Chromosomes Cancer 1999; 24:322-7. [PMID: 10092130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
The PTEN gene is involved in 10q23 deletions in several types of cancer, including glioma, melanoma, endometrial and prostate carcinomas. The PTEN gene product is a dual-specificity phosphatase with putative tumor suppressor function. Deletions and rearrangements of 10q22-25 have been reported in approximately 5%-10% of non-Hodgkin's lymphomas (NHLs), raising the possibility of PTEN involvement in these tumors. In order to address this question, we analyzed a panel of NHLs (n = 74) representative of the main histologic subtypes for mutations and homozygous deletions of PTEN. We report somatic coding/splice site mutations in 20% (2 of 10) of Burkitt's lymphoma cell lines and in 3% (2 of 64) of primary NHL cases analyzed. No homozygous deletions were found in these tumors. Interestingly, this study showed that cytogenetically characterized NHL cases (n = 6) with 10q22-q25 abnormalities displayed neither biallelic deletions nor mutations of PTEN. These results suggest that a tumor suppressor gene distinct from PTEN may be involved in 10q deletions in this subgroup of NHL cases.
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Affiliation(s)
- M P Butler
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, USA
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Abstract
To determine the status of chromosome 10q23 in primary breast carcinomas, in situ and invasive carcinomas were analysed for allelic loss using microsatellite markers spanning the 10q23 region. No LOH was seen in pure intraductal carcinomas (0/20 cases). On the other hand, LOH was observed in 40% (17/42) of invasive carcinomas (P = 0.0005). Interestingly, in situ lesions found in invasive tumors displayed LOH. Allelic loss was also significantly associated with loss of the estrogen receptor (P = 0.011). Thus, loss of the 10q23 is strongly associated with tumor progression.
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Affiliation(s)
- S Bose
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Cairns P, Evron E, Okami K, Halachmi N, Esteller M, Herman JG, Bose S, Wang SI, Parsons R, Sidransky D. Point mutation and homozygous deletion of PTEN/MMAC1 in primary bladder cancers. Oncogene 1998; 16:3215-8. [PMID: 9671402 DOI: 10.1038/sj.onc.1201855] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A new tumor suppressor gene PTEN/MMAC1 was recently isolated at chromosome 10q23 and found to be inactivated by point mutation or homozygous deletion in glioma, prostate and breast cancer. PTEN/MMAC1 was also identified as the gene predisposing to Cowden disease, an autosomal dominant cancer predisposition syndrome associated with an increased risk of breast, skin and thyroid tumors and occasional cases of other cancers including bladder and renal cell carcinoma. We screened 345 urinary tract cancers by microsatellite analysis and found chromosome 10q to be deleted in 65 of 285 (23%) bladder and 15 of 60 (25%) renal cell cancers. We then screened the entire PTEN/MMAC1 coding region for mutation in 25 bladder and 15 renal cell primary tumors with deletion of chromosome 10q. Two somatic point mutations, a frameshift and a splicing variant, were found in the panel of bladder tumors while no mutation was observed in the renal cell carcinomas. To screen for homozygous deletion, we isolated two polymorphic microsatellite repeats from genomic BAC clones containing the PTEN/MMAC1 gene. Using these new informative markers, we identified apparent retention at the gene locus indicative of homozygous deletion of PTEN/MMAC1 in four of 65 bladder and 0 of 15 renal cell tumors with LOH through chromosome 10q. Identification of the second inactivation event in six bladder tumors with LOH of 10q implies that the PTEN/MMAC1 gene is occasionally involved in bladder tumorigenesis. However, the low frequency of biallelic inactivation suggests that either PTEN/MMAC1 is inactivated by other mechanisms or it is not the only target of chromosome 10q deletion in primary bladder and renal cell cancer.
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Affiliation(s)
- P Cairns
- Head and Neck Cancer Research, Department of Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Wang SI, Parsons R, Ittmann M. Homozygous deletion of the PTEN tumor suppressor gene in a subset of prostate adenocarcinomas. Clin Cancer Res 1998; 4:811-5. [PMID: 9533551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A novel tumor suppressor gene, PTEN, which encodes a dual-specificity protein phosphatase, has recently been identified on chromosome 10q23. We have previously shown that both alleles of this gene are inactivated in three of four prostate cancer cell lines tested. To evaluate the role of inactivation of this gene in primary stage B prostate cancers, 60 cases were analyzed using Southern blotting with PTEN probes and microsatellites on 10q23. Eight of 60 cases had homozygous deletions by Southern blotting. In three of these cases, homozygous deletion was confirmed by apparent retention of heterozygosity at PTEN with loss of heterozygosity at telomeric and centromeric loci. In the remaining five cases, microsatellite analysis was consistent with homozygous deletion. Loss of heterozygosity at PTEN was found in only two cases both by microsatellite analysis and quantitative Southern blotting. No small mutations within PTEN exons were found in any tumors exhibiting alterations on 10q23. Thus, inactivation of the PTEN gene by homozygous deletion occurs in approximately 10-15% of primary stage B prostate carcinomas.
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Affiliation(s)
- S I Wang
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Wang SI, Puc J, Li J, Bruce JN, Cairns P, Sidransky D, Parsons R. Somatic mutations of PTEN in glioblastoma multiforme. Cancer Res 1997; 57:4183-6. [PMID: 9331071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alterations of the PTEN gene occur in glioblastoma multiforme. To determine the frequency of PTEN alteration, 34 consecutive glioblastomas were studied in detail. Sequencing each of the nine exons amplified from tumor DNA revealed 11 mutations. Analysis of polymorphic markers within and surrounding the PTEN gene identified an additional four homozygous deletion mutations. Loss of heterozygosity (LOH) was observed in 25 of 34 (74%) cases. All mutations occurred in the presence of LOH. PTEN was mutated in 44% (15 of 34) of all glioblastomas studied and 60% (15 of 25) of tumors with LOH on 10q. Thus, PTEN appears to be the major target of inactivation on chromosome 10q in glioblastoma multiforme.
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Affiliation(s)
- S I Wang
- Department of Pathology and Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Tashiro H, Blazes MS, Wu R, Cho KR, Bose S, Wang SI, Li J, Parsons R, Ellenson LH. Mutations in PTEN are frequent in endometrial carcinoma but rare in other common gynecological malignancies. Cancer Res 1997; 57:3935-40. [PMID: 9307275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Loss of heterozygosity of chromosome 10q has been reported in approximately 40% of endometrial carcinomas. PTEN, a candidate tumor suppressor gene located at chromosome 10q23.3, was recently identified and found to be homozygously deleted or mutated in several different types of human tumors. To determine if PTEN is a target of 10q loss of heterozygosity in carcinomas of the endometrium, we examined 32 primary endometrial carcinomas for mutations in PTEN. The tumors included the two major histopathological types of endometrial carcinoma: endometrioid (n = 26; 14 microsatellite instability (MI)-positive and 12 MI-negative) and serous (n = 6). Overall, mutations were detected in 50% of the endometrial carcinomas we analyzed. Mutations were present in 12 of 14 (86%) MI-positive and 4 of 12 (33%) MI-negative endometrioid tumors. Furthermore, mutations were found in all three histological grades of MI-positive endometrioid carcinoma. All six serous endometrial carcinomas lacked detectable mutations. To evaluate the role of PTEN in other common malignancies of the female genital tract, 12 serous ovarian carcinomas and 10 squamous cervical carcinomas were analyzed and were negative for mutations. Our results support PTEN as a tumor suppressor gene and suggest that mutations in PTEN play a significant role in the pathogenesis of the endometrioid type of endometrial carcinoma.
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Affiliation(s)
- H Tashiro
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA
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Myers MP, Stolarov JP, Eng C, Li J, Wang SI, Wigler MH, Parsons R, Tonks NK. P-TEN, the tumor suppressor from human chromosome 10q23, is a dual-specificity phosphatase. Proc Natl Acad Sci U S A 1997; 94:9052-7. [PMID: 9256433 PMCID: PMC23024 DOI: 10.1073/pnas.94.17.9052] [Citation(s) in RCA: 606] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Protein tyrosine phosphatases (PTPs) have long been thought to play a role in tumor suppression due to their ability to antagonize the growth promoting protein tyrosine kinases. Recently, a candidate tumor suppressor from 10q23, termed P-TEN, was isolated, and sequence homology was demonstrated with members of the PTP family, as well as the cytoskeletal protein tensin. Here we show that recombinant P-TEN dephosphorylated protein and peptide substrates phosphorylated on serine, threonine, and tyrosine residues, indicating that P-TEN is a dual-specificity phosphatase. In addition, P-TEN exhibited a high degree of substrate specificity, showing selectivity for extremely acidic substrates in vitro. Furthermore, we demonstrate that mutations in P-TEN, identified from primary tumors, tumor cells lines, and a patient with Bannayan-Zonana syndrome, resulted in the ablation of phosphatase activity, demonstrating that enzymatic activity of P-TEN is necessary for its ability to function as a tumor suppressor.
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Affiliation(s)
- M P Myers
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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Liaw D, Marsh DJ, Li J, Dahia PL, Wang SI, Zheng Z, Bose S, Call KM, Tsou HC, Peacocke M, Eng C, Parsons R. Germline mutations of the PTEN gene in Cowden disease, an inherited breast and thyroid cancer syndrome. Nat Genet 1997; 16:64-7. [PMID: 9140396 DOI: 10.1038/ng0597-64] [Citation(s) in RCA: 1342] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cowden disease (CD) is an autosomal dominant cancer predisposition syndrome associated with an elevated risk for tumours of the breast, thyroid and skin. Lhermitte-Duclos disease (LDD) cosegregates with a subset of CD families and is associated with macrocephaly, ataxia and dysplastic cerebellar gangliocytomatosis. The common feature of these diseases is a predisposition to hamartomas, benign tumours containing differentiated but disorganized cells indigenous to the tissue of origin. Linkage analysis has determined that a single locus within chromosome 10q23 is likely to be responsible for both of these diseases. A candidate tumour suppressor gene (PTEN) within this region is mutated in sporadic brain, breast and prostate cancer. Another group has independently isolated the same gene, termed MMAC1, and also found somatic mutations throughout the gene in advanced sporadic cancers. Mutational analysis of PTEN in CD kindreds has identified germline mutations in four of five families. We found nonsense and missense mutations that are predicted to disrupt the protein tyrosine/dual-specificity phosphatase domain of this gene. Thus, PTEN appears to behave as a tumour suppressor gene in the germline. Our data also imply that PTEN may play a role in organizing the relationship of different cell types within an organ during development.
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Affiliation(s)
- D Liaw
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Li J, Yen C, Liaw D, Podsypanina K, Bose S, Wang SI, Puc J, Miliaresis C, Rodgers L, McCombie R, Bigner SH, Giovanella BC, Ittmann M, Tycko B, Hibshoosh H, Wigler MH, Parsons R. PTEN, a putative protein tyrosine phosphatase gene mutated in human brain, breast, and prostate cancer. Science 1997; 275:1943-7. [PMID: 9072974 DOI: 10.1126/science.275.5308.1943] [Citation(s) in RCA: 3509] [Impact Index Per Article: 130.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mapping of homozygous deletions on human chromosome 10q23 has led to the isolation of a candidate tumor suppressor gene, PTEN, that appears to be mutated at considerable frequency in human cancers. In preliminary screens, mutations of PTEN were detected in 31% (13/42) of glioblastoma cell lines and xenografts, 100% (4/4) of prostate cancer cell lines, 6% (4/65) of breast cancer cell lines and xenografts, and 17% (3/18) of primary glioblastomas. The predicted PTEN product has a protein tyrosine phosphatase domain and extensive homology to tensin, a protein that interacts with actin filaments at focal adhesions. These homologies suggest that PTEN may suppress tumor cell growth by antagonizing protein tyrosine kinases and may regulate tumor cell invasion and metastasis through interactions at focal adhesions.
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Affiliation(s)
- J Li
- Department of Pathology, College of Physicians & Surgeons, Columbia University, 630 West 168 Street, New York, NY 10032, USA
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Huss JM, Wang SI, Astrom A, McQuiddy P, Kasper CB. Dexamethasone responsiveness of a major glucocorticoid-inducible CYP3A gene is mediated by elements unrelated to a glucocorticoid receptor binding motif. Proc Natl Acad Sci U S A 1996; 93:4666-70. [PMID: 8643461 PMCID: PMC39336 DOI: 10.1073/pnas.93.10.4666] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Elements responsible for dexamethasone responsiveness of CYP3A23, a major glucocorticoid-inducible member of the CYP3A gene family, have been identified. DNase I footprint analysis of the proximal promoter region revealed three protected sites (sites A, B, and C) within the sequence defined by -167 to -60. Mutational analysis demonstrated that both sites B and C were necessary for maximum glucocorticoid responsiveness and functioned in a cooperative manner. Interestingly, neither site contained a glucocorticoid responsive element. Embedded in site C was an imperfect direct repeat (5'-AACTCAAAGGAGGTCA-3'), showing homology to an AGGTCA steroid receptor motif, typically recognized by the estrogen receptor family, while site B contained an ATGAACT direct repeat; these core sequences were designated dexamethasone response elements 1 and 2 (DexRE-1 and -2), respectively. Neither element has previously been associated with a glucocorticoid-activated transcriptional response. Conversion of the DexRE-1 to either a perfect thyroid hormone or vitamin D3 responsive element further enhanced induction by dexamethasone. Gel-shift analysis demonstrated that glucocorticoid receptor did not associate with either DexRE-1 or -2; hence, glucocorticoid receptor does not directly mediate glucocorticoid induction of CYP3A23. These unusual features suggest an alternate pathway through which glucocorticoids exert their effects.
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Affiliation(s)
- J M Huss
- Department of Oncology, McArdle Laboratory, University of Wisconsin, Madison, 53706, USA
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Wang SI, Frieden BR. Effects of third-order spherical aberration on the 3-D incoherent optical transfer function. Appl Opt 1990; 29:2424-2432. [PMID: 20563184 DOI: 10.1364/ao.29.002424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We derive the expression for the 3-D incoherent optical transfer function when third-order spherical aberration is present. The normalized verision of the transfer function is numerically calculated for various amounts of spherical aberration. We find the effects of the aberration to be highly dependent on the spatial frequency in the longitudinal direction. We also calculate a structure content parameter, as a quality criterion, from the normalized transfer function. The structure content parameter dependence on spherical aberration is well-fit by a simply Cauchy curve for aberrations out to two waves at the margin.
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Granneman GR, Wang SI, Kesterson JW, Machinist JM. The hepatotoxicity of valproic acid and its metabolites in rats. II. Intermediary and valproic acid metabolism. Hepatology 1984; 4:1153-8. [PMID: 6437961 DOI: 10.1002/hep.1840040610] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The role of metabolites in valproic acid (VPA)-associated hepatotoxicity was studied in rats. The most steatogenic mono-unsaturated metabolite, 4-en-VPA, caused the greatest changes in indicators of beta-oxidation inhibition (dicarboxylic aciduria, beta-hydroxybutyrate reduction); however, the biochemical effects were much less pronounced than those reported for hypoglycin. Steatosis in VPA-treated rats occurred only at nearly lethal doses. Phenobarbital induction was confirmed as a predisposing factor; however, it appeared not to greatly enhance production of 4-en-VPA or its recognized metabolites, which collectively comprised only 0.5% of the dose. Elevated oxo-VPA metabolites in serum and 2-propylglutarate in liver were associated with toxicity. Among the newly discovered minor metabolites with possible biologic effects were diols (suggesting epoxide precursors) and a series of dienes and trienes. The rarity of severe human hepatotoxicity indicates that, normally, beta-oxidation inhibition is compensated, and cellular defense mechanisms prevail over reactive metabolites. This requires adequate nutrition; on the other hand, severe glycogen depletion may promote toxicity by compromising glucuronidation, the major clearance route. Other literature comments are also supported: (i) caution is indicated for patients with various unusual congenital disorders (e.g., organic acidurias or other mitochondrial defects), and (ii) monotherapy obviates both the predisposition to toxicity and the requirement of large doses to produce therapeutic levels.
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Abstract
The metabolic routes of valproic acid (VPA) were studied by i.p. administration of the mono-unsaturated and hydroxylated metabolites to rats. Conjugation with glucuronic acid was a major metabolic route for VPA and its metabolites. Conjugation with glycine was a minor route for VPA, but was of more importance with the unsaturated metabolites. The hydroxylated metabolites, which were further oxidized to oxo-derivatives and subsequently to the dicarboxylic acids, were not metabolically dehydrated to form unsaturated metabolites. Multiple metabolic pathways, including dehydrogenation, isomerization, hydration, hydroxylation, reduction and epoxidation were inferred from the metabolites obtained after dosage of the unsaturated metabolites. Six dien-VPA metabolites were detected in VPA-treated rats, four of which are present in patients. It was concluded that 3-en-VPA and 4-en-VPA pathways, originating through dehydrogenation, are distinct from the omega- and omega-1-hydroxylation pathways. Enzyme induction from co-administration of phenobarbital caused enhancement of the minor omega-1-oxidation pathway, yet the largest effect on clearance came from increases in glucuronidation. Mitochondrial processes were unaffected, resulting in decreased contribution to the total clearance.
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