title: The increase of phospholipase C activity induced by orotic acid is unrelated to lipid peroxidation.
abstract: Liver phospholipase-C (PL-C) activity proved to be promptly modified in rats fed with an orotic acid (OA) supplemented diet; an increased of PL-C basal activity was demonstrated after 2 days of diet. In the present work the possible involvement of lipid peroxidation was investigated, since 4-hydroxynonenal (HNE) and 4-hydroxyoctenal (HOE), two end-products of lipid peroxidation, have been shown to induce a strong stimulation of hepatic PL-C. Membrane-bound PL-C activity was evaluated together with the rate of TBArs production by liver homogenates obtained from rats fed with a diet containing 1% OA for 2 and 5 days. PL-C activity was measured by following the rate of formation of Ins-P3 from labelled PtdIns-P2 added to isolated liver membranes. TBArs production was unchanged in the livers of rats fed the OA diet, while basal and GTPgammaS-stimulated PL-C activity increased; furthermore PL-C stimulation by bombesin was deeply impaired by OA.
mesh_terms: D000818:Animals; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism; D008297:Male; D009963:Orotic Acid / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014280:Triglycerides / Q000097:blood; D010738:Type C Phospholipases / Q000378:metabolism*