RESUMO
Objective To develop and validate a simple and reliable HPLC method for the analysis of flee and total carnitine in human serum and to investigate its clinical significance. Methods After proteins in serum were precipitated with a precipitating reagent, carnitine in serum was derivatized to form its ester. HPLC separation of the sample solution was performed on a Lichrospher SiO2 column and detected by ultraviolet absorbance at 260 nm. A mobile phase composed of acetonitrile-citric acid-triethanolamine was found to be the most suitable for this separation at a flow rate of 1.2 ml/min and enabled the baseline separation of the carnitine from interferences with isocratic elution. The free and total carnitine levels in serum were studied in 347 subjects. Results Under the chromatographic conditions described, the carnitine derivative had a retention time of approximately 10 min. Good separation and detectability of carnitine in human serum sample were obtained. The method proved to be linear in the range of carnitine from 0 μmol/L to 400 μmol/L The relative standard deviations of within-assay ( n = 5 ) for free and total carnitine analysis were 3.36% and 1.97% , respectively, and between-assay (n =7) for free and total carnitine analysis were 3.04% and 1.77%, respectively. The average recovery was 98. 2% for free camitine and 96.3% for total carnitine, respectively. The average L-carnitine concentrations in the 347 subjects were as follows: total carnitine (52. 2 ± 8. 6 ) μmol/L, free carnitine ( 42. 3 ± 8. 3 ) μmol/L and acylcarnitine ( 9. 9 ± 2. 9 )μmol/L in the male group ( n = 182), and total carnitine (48.2 ± 9. 9 ) μmol/L, free camitine ( 37.9 ±8. 7) μmol/L and acylcarnitine ( 10. 3 ± 3.5 ) μmol/L in the female group ( n = 165 ). Statistical analysis showed that total and free carnitine levels of male were higher than that of female ( P <0. 01 ) while there was not statistical difference of acylcarnitine levels between two groups ( P > 0. 05). Conclusion The method has been successfully applied to the simultaneous determination of free and total carnitine in serum with good sensitivity, specificity and repeatability, and this is a useful guidance for the clinic therapy and the mechanism study on the diseases associated with carnitine.
RESUMO
Objective: Carnitine,the only carrier for the fatty acid crossing into mitochondria for oxidization,has a significant effect on the metabolism serum lipids.The purpose of this study is to investigate the effects of different doses of carnitine supplement on serum lipids in hyperlipemia rabbits. Methods: Twenty-eight rabbits were equally randomized into a control and three experimental groups,the former fed on high-fat diet,and the latter on carnitine at the dose of 100,200 and 400 mg/kg respectively every day in addition to high-fat diet.Blood samples were collected from the central artery of the rabbits for the measurement of the total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),apolipoprotein B(ApoB) and free carnitine in the serum,their body weight obtained at 0,1,2,3,4 and 5 weeks,and the effects of different doses of carnitine supplement were observed on serum lipids.Results: All the 28 rabbits were included in the result analysis.The hyperlipemia model was successfully established after 4 weeks of high-fat diet.Compared with the control group,the experimental groups showed a remarkable decrease in the levels of TC,TG,LDL-C and AapoB and an increase in that of HDL-C in the serum,positively correlated with the dose and time of carnitine supplement.With the lengthening of time,the effects of different doses of carnitine supplement on the serum lipids was gradually decreased.Conclusion: Carnitine supplement can inhibit the increase of the levels of TC,TG,LDL-C and AapoB in the serum of the rabbits with hyperlipemia induced by high-fat diet and the effect is positively correlated with the dose and time of carnitine supplement.