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11-Deoxycorticosterone

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Mitsuhiro Okamoto – One of the best experts on this subject based on the ideXlab platform.

  • dahl s salt resistant normotensive rat has mutations in cytochrome p450 11 beta but the salt sensitive hypertensive rat does not
    Journal of Biological Chemistry, 1993
    Co-Authors: Naomichi Matsukawa, Yasuki Nonaka, Jitsuo Higaki, Masahiro Nagano, Hiroshi Mikami, Toshio Ogihara, Mitsuhiro Okamoto
    Abstract:

    Abstract Molecular cloning of cytochrome P450(11 beta) cDNAs from the adrenal glands of Dahl’s salt-sensitive hypertensive (DS) and salt-resistant normotensive (DR) rats was performed using a combined technique of the first strand cDNA synthesis by reverse transcriptase followed by polymerase chain reaction. The cDNA sequence of P450(11 beta)-DS was identical to that of wild type P450(11 beta). In contrast, the clone obtained from the DR rat contained six nucleotide substitutions causing five amino acid alterations (Arg-127–>Cys, Val-351–>Ala, Val-381–>Leu, Ile-384–>Leu, and Val-443–>Met). When the two cDNAs were expressed in COS-7 cells and steroid conversion rates of the transformed cells were determined, a ratio of 18-hydroxylation to 11 beta-hydroxylation of 11-Deoxycorticosterone by P450(11 beta)-DS-expressed cells was 0.58, whereas that by P450(11 beta)-DR-expressed cells was 0.23. Plasma levels of 18-hydroxy-11-Deoxycorticosterone and corticosterone (the 11 beta-hydroxylation product of 11-Deoxycorticosterone) in DS and DR rats well reflected the steroidogenic activities of the two P450s. These results suggest that the characteristic plasma steroid level of the DR rat is caused by the mutations in P450(11 beta) gene and may act to maintain the normotensive blood pressure in this rat strain during sodium loading.

  • Functional expression of the cDNAs encoding rat 11β-hydroxylase [cytochrome P450(11β)] and aldosterone synthase [cytochrome P450(11β, aldo)]
    European journal of biochemistry, 1991
    Co-Authors: Yasuki Nonaka, Mitsuhiro Okamoto
    Abstract:

    Expression plasmids containing two cDNAs of a rat cytochrome P450(11β) family, pcP450(11β)-62 [Nonaka, Y., Matsukawa, N., Morohashi, K., Omura, T., Ogihara, T., Teraoka, H. & Okamoto, M. (1989) FEBS Lett. 255, 21–26] and pcP450(11β, aldo)-46 [Matsukawa, N., Nonaka, Y., Ying, Z., Higaki, J., Ogihara, T. & Okamoto, M. (1990) Biochem. Biophys. Res. Commun. 169, 245–252], were constructed and introduced into COS-7 cells by electroporation. Enzymatic activities of the expressed cytochromes P450(11β) and P450(11β, aldo) were determined by using 11-Deoxycorticosterone, corticosterone, 18-hydroxy-11-Deoxycorticosterone, 18-hydroxycorticosterone, or 19-hydroxy-11-Deoxycorticosterone as a substrate. Cytochrome P450(11β) catalyzed 11β-, 18-and 19-hydroxylations of 11-Deoxycorticosterone and 19-oxidation or 19-hydroxy-11-Deoxycorticosterone at substantial rates, 18-hydroxylation of corticosterone at a very low rate, but no aldosterone production. Cytochrome P450(11β, aldo) catalyzed 11β- and 18-hydroxylations of 11-Deoxycorticosterone, 18-hydroxylation of corticosterone and aldosterone production from 11-Deoxycorticosterone or corticosterone. But neither 19-hydroxylation of 11-Deoxycorticosterone nor 19-oxidation of 19-hydroxy-11-Deoxycorticosterone was catalyzed by cytochrome P450(11β, aldo).

Yasuki Nonaka – One of the best experts on this subject based on the ideXlab platform.

  • dahl s salt resistant normotensive rat has mutations in cytochrome p450 11 beta but the salt sensitive hypertensive rat does not
    Journal of Biological Chemistry, 1993
    Co-Authors: Naomichi Matsukawa, Yasuki Nonaka, Jitsuo Higaki, Masahiro Nagano, Hiroshi Mikami, Toshio Ogihara, Mitsuhiro Okamoto
    Abstract:

    Abstract Molecular cloning of cytochrome P450(11 beta) cDNAs from the adrenal glands of Dahl’s salt-sensitive hypertensive (DS) and salt-resistant normotensive (DR) rats was performed using a combined technique of the first strand cDNA synthesis by reverse transcriptase followed by polymerase chain reaction. The cDNA sequence of P450(11 beta)-DS was identical to that of wild type P450(11 beta). In contrast, the clone obtained from the DR rat contained six nucleotide substitutions causing five amino acid alterations (Arg-127–>Cys, Val-351–>Ala, Val-381–>Leu, Ile-384–>Leu, and Val-443–>Met). When the two cDNAs were expressed in COS-7 cells and steroid conversion rates of the transformed cells were determined, a ratio of 18-hydroxylation to 11 beta-hydroxylation of 11-Deoxycorticosterone by P450(11 beta)-DS-expressed cells was 0.58, whereas that by P450(11 beta)-DR-expressed cells was 0.23. Plasma levels of 18-hydroxy-11-Deoxycorticosterone and corticosterone (the 11 beta-hydroxylation product of 11-Deoxycorticosterone) in DS and DR rats well reflected the steroidogenic activities of the two P450s. These results suggest that the characteristic plasma steroid level of the DR rat is caused by the mutations in P450(11 beta) gene and may act to maintain the normotensive blood pressure in this rat strain during sodium loading.

  • Functional expression of the cDNAs encoding rat 11β-hydroxylase [cytochrome P450(11β)] and aldosterone synthase [cytochrome P450(11β, aldo)]
    European journal of biochemistry, 1991
    Co-Authors: Yasuki Nonaka, Mitsuhiro Okamoto
    Abstract:

    Expression plasmids containing two cDNAs of a rat cytochrome P450(11β) family, pcP450(11β)-62 [Nonaka, Y., Matsukawa, N., Morohashi, K., Omura, T., Ogihara, T., Teraoka, H. & Okamoto, M. (1989) FEBS Lett. 255, 21–26] and pcP450(11β, aldo)-46 [Matsukawa, N., Nonaka, Y., Ying, Z., Higaki, J., Ogihara, T. & Okamoto, M. (1990) Biochem. Biophys. Res. Commun. 169, 245–252], were constructed and introduced into COS-7 cells by electroporation. Enzymatic activities of the expressed cytochromes P450(11β) and P450(11β, aldo) were determined by using 11-Deoxycorticosterone, corticosterone, 18-hydroxy-11-Deoxycorticosterone, 18-hydroxycorticosterone, or 19-hydroxy-11-Deoxycorticosterone as a substrate. Cytochrome P450(11β) catalyzed 11β-, 18-and 19-hydroxylations of 11-Deoxycorticosterone and 19-oxidation or 19-hydroxy-11-Deoxycorticosterone at substantial rates, 18-hydroxylation of corticosterone at a very low rate, but no aldosterone production. Cytochrome P450(11β, aldo) catalyzed 11β- and 18-hydroxylations of 11-Deoxycorticosterone, 18-hydroxylation of corticosterone and aldosterone production from 11-Deoxycorticosterone or corticosterone. But neither 19-hydroxylation of 11-Deoxycorticosterone nor 19-oxidation of 19-hydroxy-11-Deoxycorticosterone was catalyzed by cytochrome P450(11β, aldo).

Eduardo N. Cozza – One of the best experts on this subject based on the ideXlab platform.

  • Inhibition of aldosterone production in rat adrenal mitochondria by 18-ethynyl-11-Deoxycorticosterone: a simple model for kinetic interpretation of mechanism-based inhibitors.
    Journal of biochemistry, 2001
    Co-Authors: Laura Matković, Celso E. Gomez-sanchez, Eduardo N. Cozza
    Abstract:

    A simple mathematical model for studying mechanism-based inhibitors (MBIs) is presented. The mathematical equations are deduced for an experimental protocol consisting of a first incubation of the enzyme in the presence of MBI followed by a washing protocol to eliminate free MBI. Finally enzyme activity (initial velocity) is measured with specific substrate. The representation of the final equation obtained is a straight line, and the MBI-specific association constant of velocity (k) can be calculated from its slope. The mathematical model was then challenged with the effect of 18-ethynyl-11-Deoxycorticosterone (18-EtDOC) as an MBI on aldosterone biosynthesis from 11-Deoxycorticosterone (DOC) in rat adrenal mitochondria. The last step of the mitochondrial biosynthesis of aldosterone consists of the conversion of DOC into corticosterone (B) or 18-hydroxy-11-Deoxycorticosterone (18-OHDOC), and both steroids can then be transformed into aldosterone. The k (mM(-1) x min(-1)) values obtained for 18-EtDOC were: 451 +/- 36 for DOC to aldosterone; 177 +/- 16 for B to aldosterone; 175 +/- 15 for 18-OHDOC to aldosterone; and 2.7 +/- 0.2 for DOC to B. These results show that this MBI practically does not affect the metabolism of DOC to B in our enzyme preparation and that conversions of B and 18-OHDOC into aldosterone are catalyzed by the same enzyme.

  • Cortisol: a tool to study aldosterone biosynthesis in rats.
    Endocrine research, 1995
    Co-Authors: Laura Matković, Celso E. Gomez-sanchez, Carlos P. Lantos, Eduardo N. Cozza
    Abstract:

    Corticosterone (B) and 18-hydroxy-11-Deoxycorticosterone (18OHDOC) but not 11-Deoxycorticosterone (DOC) displaced cortisol (F) specifically bound to rat adrenal mitochondria. F competitively inhibited aldosterone formation from B, 18OHB and 18OHDOC but did not inhibit conversions of DOC to B or 18OHDOC. High concentrations of DOC increased its conversion to 18OHDOC rather than B.