Dietary L-carnitine alters the metabolism and body status of vitamin E in rats

L-Carnitine (3-carboxy-2[R]-hydroxy-N,N,N-trimethyl-1-propanaminium, inner salt, CN) has been implicated as an antioxidant. The first study was conducted to determine if dietary CN at 150 mg/kg diet improves the intestinal absorption of alpha-tocopherol (alphaTP) in ovariectomized (OX) rats. OX adult rats were weight matched and assigned to two groups: one fed a modified AIN-93G diet containing alphaTP-stripped soybean oil and no CN (-CN) and the other fed the same diet but containing CN at 150 mg/kg diet (+CN). The lymphatic absorption of alphaTP for 8 h in +CN was significantly higher (P < 0.05) than in -CN rats. The second study was conducted to determine if dietary CN affects the liver concentration and biliary secretion of alphaTP in OX rats. The liver concentration of alphaTP in +CN was significantly higher than in -CN rats. The biliary secretion of alphaTP for 8 h in +CN was significantly higher than in -CN rats. The third study was conducted to examine if dietary sodium pivalate (trimethylacetic acid, PV) affects the liver concentration and biliary secretion of alphaTP by inducing CN deficiency in OX rats. The liver concentration of total CN (TCN) in PV was significantly lower than in control (CT) and CN rats. The rates of bile flow and biliary secretions of alphaTP and phosphatidylcholine (PC) in PV and CN were significantly higher than in CT rats during which period 5% glucose phosphate buffered saline (PBS) devoid of lipids was infused intraduodenally. The fourth study was conducted to determine if dietary CN and estrogen (ES) replacement affect the serum level of alphaTP in OX rats. Dietary CN significantly decreased the concentrations of alphaTP, cholesterol (CH), and phospholipid (PL) in the total serum and VLDL + LDL fraction. ES replacement significantly increased the levels of alphaTP, CH, and PL in the total serum and HDL and VLDL + LDL fractions. The fifth study was conducted to determine if dietary CN affects the adipose tissue weight and concentrations of alphaTP and fatty acids in adipose tissues during food restriction. During food restriction, the weights of retroperitoneal adipose tissue (RPA) and epididymal adipose tissue (EDA) in +CN were significantly lower than in -CN rats. Dietary CN significantly increased the concentrations of alphaTP in RPA and EDA. Dietary CN significantly increased the concentrations of 20:5n-3 and 22:6n-3 in RPA and the concentrations of the fatty acids were significantly correlated with the concentration of alphaTP. The results of this study demonstrate that dietary L-carnitine enhances the body status of vitamin E and favorably alter the serum and tissue lipid profiles in ovariectomized female rats and in male rats subjected to food restriction.