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Long‐term, physiological dose of prednisolone treatment alters vitamin B6 metabolism in vivo
Author(s) -
Chang HsinYueh,
Chiang EnPei Isabel
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.537.17
Subject(s) - psl , pyridoxal , endocrinology , medicine , prednisolone , in vivo , pyridoxamine , vitamin , pyridoxal phosphate , chemistry , glucocorticoid , metabolism , pharmacology , biology , enzyme , biochemistry , geometry , mathematics , microbiology and biotechnology , cofactor
Earlier studies reported that B6 metabolic enzymes were reduced in adrenalectomized rats that could be restored by short‐term injection of very high dose glucocorticoids. Prednisolone (PSL) is a glucocorticoid commonly used for long‐term treatment of chronic inflammatory and autoimmune disorders. In the present study we investigated the impacts of long‐term physiological dose of PSL on vitamin B6 metabolism in vivo. Male C57BL/6J mice received either PBS (control), 0.1 mg PSL/kg (low dose), or 1 mg PSL/kg (medium dose) i.p. once every other day for up to 7 months, to mimic the regimen of PSL in humans with chronic disorders. PSL did not alter steady state B6 vitamers or B6 metabolic enzymes in erythrocytes. However, PSL (1mg/kg) significantly increased plasma pyridoxal 5′‐phosphate (PLP), pyridoxal (PL) and 4‐pyridoxic acid (PA) levels (P<0.05). Furthermore, PSL increased PL level in the muscle in a dose dependent manner. PSL significantly induced hepatic pyridoxal kinase (PDXK) and pyridoxamine 5′‐phosphate oxidase activity (PMPO), but reduced hepatic pyridoxamine 5′‐phosphate (PMP) concentrations. Our study suggests that long‐term low/medium dose PSL can induce hepatic PDXK and PMPO activities that may convert hepatic PMP to PLP, leading to increased PL in the circulation and promote mobilization of B6 vitamers among tissues. ( This project was supported by Dept of Health in Taiwan DOH 97‐TD‐D‐113‐97011) Grant Funding Source: ASN