title: Retinol oxidation to retinoic acid in human thyroid glandular cells.
abstract: Abstract Retinoic acid is regarded as the retinol metabolite that controls proliferation and differentiation of epithelial cells. In the present study, we investigated the potential role of xanthine dehydrogenase (XDH) in retinoic acid biosynthesis in human thyroid glandular cells (HTGC). In particular, we observed that cellular retinoids binding proteins (CRBPs) are also implicated in the biosynthetic pathway leading to retinoic acid formation in primary cultures of HTGC, as we have already reported for human mammary epithelial cells (HMEC). After partial protein purification, the enzyme responsible for retinoic acid biosynthesis was identified and quantified as XDH by immunoassay, by its ability to oxidize xanthine to uric acid and its sensitivity to the inhibitory effect of oxypurinol. The evidence of XDH-driven formation of retinoic acid in HTGC cultures further corroborates the potential role of XDH in retinoic acid biosynthesis in the epithelia.
authors: Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, Università degli Studi di Palermo , Palermo , Italy .
authors: Gennaro
authors: G
authors: Taibi
authors: Maria Concetta
authors: MC
authors: Gueli
authors: Concetta M A
authors: CM
authors: Nicotra
authors: Letizia
authors: L
authors: Cocciadiferro
authors: Giuseppe
authors: G
authors: Carruba
mesh_terms: D000328:Adult; D057075:Enzyme Assays; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D010117:Oxypurinol / Q000494:pharmacology; D061251:Primary Cell Culture; D054840:Retinol-Binding Proteins, Cellular / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D014212:Tretinoin / Q000378:metabolism*; D014527:Uric Acid / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism*; D019820:Xanthine / Q000378:metabolism; D014968:Xanthine Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A; D019820:Xanthine; D014527:Uric Acid; D014212:Tretinoin; D014968:Xanthine Dehydrogenase; D010117:Oxypurinol
keywords: CRABPs; CRBPs; human thyroid glandular cells; retinoic acid biosynthesis; retinol oxidation; xanthine dehydrogenase