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Decreased prereceptorial glucocorticoid activating capacity in starvation due to an oxidative shift of pyridine nucleotides in the endoplasmic reticulum
Author(s) -
Kereszturi Éva,
Kálmán Fanni S.,
Kardon Tamás,
Csala Miklós,
Bánhegyi Gábor
Publication year - 2010
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2010.10.053
Subject(s) - endoplasmic reticulum , cortisone , microsome , metyrapone , medicine , chemistry , endocrinology , dehydrogenase , nucleotide , 11β hydroxysteroid dehydrogenase type 1 , cytosol , oxidative phosphorylation , redox , biochemistry , biology , enzyme , gene , organic chemistry
Redox state of pyridine nucleotides of the endoplasmic reticulum (ER) lumen was determined in different nutritional conditions. NADPH‐dependent cortisone reduction and NADP + ‐dependent cortisol oxidation were measured in rat liver microsomes, by utilizing the luminal 11β‐hydroxysteroid dehydrogenase type 1 activity. Cortisone reduction decreased, while cortisol oxidation increased during onward starvation, showing that the luminal NADPH/NADP + ratio was substantially decreased. Cortisone or metyrapone addition caused a smaller decrease in NADPH fluorescence in microsomes from starved rats. The results demonstrate that nutrient supply is mirrored by the redox state of ER luminal pyridine nucleotides.