title: In vitro effects of flavin adenine dinucleotide and dexamethasone phosphate on high molecular weight phosphate compounds in the rat lens.
abstract: In order to clarify the pathogenesis of steroid cataracts as one of the side effects from the administration of dexamethasone phosphate (DX), investigations were conducted into the in vitro effects of flavin adenine dinucleotide (FAD) and DX on the macromolecular phosphate compounds separated from the lens supernatant using Sephadex G-50. The author found that phosphate turnover in the macromolecular phosphate compounds was reduced by DX, however, the loss was partially prevented by the addition of FAD. These macromolecular phosphate compounds were identified as nucleic acids, mostly RNA and a small amount of protein. Therefore, the author employed an experiment using the incorporation of tritiated uridine and thymidine into this macromolecular phosphate compounds. The incroporation of uridine-3H into RNA and thymidine-3H into DNA was inhibited by the addition of DX, however, this loss of turnover rate was partially prevented in RNA by the simultaneous administration of FAD, whereas no change was found in the DNA fraction treated with FAD. These results suggest that there is a close relationhip between FAD and the turnover of macromolecular phosphate compounds in the lens and that FAD, as a new physiological role, has an ability to reactivate the depressed turnover of RNA resulting from a DX administration. The possible role of nucleic acid turnover on the pathogenesis of steroid cataracts was discussed with relationship to adrenal dysfunction leading to a phosphorylation insufficiency caused by DX.
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D005182:Flavin-Adenine Dinucleotide / Q000494:pharmacology*; D007908:Lens, Crystalline / Q000378:metabolism*; D046911:Macromolecular Substances; D008297:Male; D010710:Phosphates / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D051381:Rats
chemical_list: D046911:Macromolecular Substances; D010710:Phosphates; D005182:Flavin-Adenine Dinucleotide; D012313:RNA; D003907:Dexamethasone; D004247:DNA