Changes in key enzymes of hepatic lipid metabolism induced by commercial oil-supplemented diets

HURTADO DE CATALFO, GRACIELA E.; TACCONI DE ALANIZ, MARÍA JOSEFA; MARRA, CARLOS ALBERTO

Villa Carlos Paz, Córdoba

Congreso; 44 Reunión Nac. Soc. Argentina de Invest. Bioqca. y Biología Molecular (SAIB); 2008

SAIB

Previous studies from our lab demonstrated that commercial oils used as dietary lipid source (70 gr/Kg diet for 60 days) can induce oxidative stress in liver, brain, kidney, and testis of Wistar rats fed soybean (S), coconut (C), olive (O) or grape-seed (G) oil-supplemented diets.  In liver, these changes increased free radical production in G and S dietary groups, comparaed with C, and O rats. We investigated the impact of these diets on the main hepatic enzymes involved in fatty acid (FA) metabolism. Long-chain FA synthetase was decreased in S and G groups compared with O and C.  D9 Microsomal FA desaturase activities for palmitic and stearic acids were decreased in S and G groups, while D6 (linoleic and a-linolenic FA as substrates), and the D5 (arachidonate), decreased in the order O>S>G>C. Phospholipase A2 activity was incremented in the order G>S>O>C. Rate of b-oxidation (mitochondrial fraction) was depressed in G and S group compared with O and C. FA-CoA synthetase from S and G was incremented compared with that of O and C groups. Nitrite+nitrate concentration in liver homogenates parallel the concentration of ONOO.- which directly correlated with [Ca]. This finding may be the causal factor that explains the observed changes. Thus, dietary lipid may have a direct influence on lipid metabolism through the modifications induced in some of the most important enzyme activities.