• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1568-1575
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• 2000

Growing pigs (N=25; 18 kg) were used to study effects of L-carnitine and protein intake on plasma carnitine, energy and carnitine balance, and carnitine biosynthesis. Corn-soybean meal basal diets containing low or high protein (13.6% or 18%) were formulated so that protein accretion would be limited by metabolizable energy (ME). Each basal diet was supplemented with 0 or 500 mg/kg L-carnitine and limit fed to pigs for 10 d in a balance trial. Final carnitine concentration was compared with weight/age matched pigs measured on d 0 to calculate carnitine retention rates. Supplementation of carnitine increased (p<0.01) plasma free carnitine (by 250%), short-chain (by 160%) and long-chain acyl-carnitine concentrations (by 80%) irrespective of blood sampling time (p<0.01). The proportion of long-chain carnitine esters decreased by 40% (p<0.01) by carnitine supplementation; whereas, the proportion of short-chain acyl-carnitine concentration was not changed (p>0.10). All criteria of energy balance were unaffected by L-carnitine (p>0.10). Total body carnitine retention was increased by 450% over unsupplemented controls (p<0.01). Carnitine biosynthesis rates in pigs fed diets without L-carnitine were estimated at 6.71 and $10.63{\mu}mol{\cdot}kg^{-1}{\cdot}d^{-1}$ in low protein and high protein groups, respectively. In supplemented pigs, L-carnitine absorption and degradation in the intestinal tract was estimated at 30-40% and 60-70% of L-carnitine intake, respectively. High protein feeding effect did not affected plasma carnitine concentrations, carnitine biosynthesis or carnitine retention (p>0.10). We conclude that endogenous carnitine biosynthesis may be adequate to maintain sufficient tissue levels during growth, but that supplemental dietary carnitine (at 500 ppm) sufficiently increased plasma acyl-carnitine and total body carnitine.

• Journal of Nutrition and Health
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• v.36 no.7
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• pp.720-728
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• 2003

This study was conducted to evaluate changes in plasma concentration and urinary excretion of carnitine, as well as plasma lipid level and fatty acid composition, caused by short term supplementation of carnitine in humans. Ten healthy male subjects (21.2 $\pm$ 0.5 years old) received oral carnitine supplementation (4 g/day) as tablets for two weeks. Fasting blood and random urine samples were collected from each subject both prior to and at the end of carnitine supplemention program. Following the 2 weeks of carnitine supplementation, plasma total carnitine (TCNE) concentration increased 20% (85.1 $\pm$ 7.4 vs 67.3 $\pm$ 9.1 $\mu$ mol/1, p> 0.05), while urinary excretion of total carnitine increased ten times compared to the value measured prior to the supplementation (3051 $\pm$ 692 vs 278 $\pm$ 90.1 $\mu$ mol/g creatinine, p < 0.01). Non-esterified carnitine (NEC) comprised from 71 to 88% of TCNE in plasma, and from 32 to 40% of TCNE excreted in the urine. Two weeks of carnitine supplementation in healthy adults significantly elevated plasma level of acid soluble acylcarnitine (ASAC) which is esterified mostly with short chain fatty acids (21.6 $\pm$ 1.6 $\mu$ mol/l) compared to the value measured prior to the supplementation (6.4 $\pm$ 0.8 $\mu$ mol/l) (p < 0.05). Carnitine supplementation significantly increased plasma HDL-cholesterol level (p < 0.05), and decreased the atherogenic index (p < 0.05), but failed to cause any significant change in plasma levels of total cholesterol, triglyceride, and free fatty acids. Plasma triglyceride and phospholipid fatty acid compositions were not significaly affected as well by the oral supplementation of carnitine in subjects with normal range of blood lipid levels.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.237-242
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• 2001

Colostrum deprived, newborn pigs (N=12, $1.64{\pm}0.05kg$) were used to study the renal threshold of carnitine, and effects of emulsified medium-chain triglyceride (MCT, tri-8:0) feeding on kinetics of plasma carnitine and urinary carnitine excretion. An arterial catheter was inserted through an umbilical artery, and a bladder catheter was inserted via the urachus. Piglets were oro-gastrically gavaged with one of six carnitine levels (0, 60, 120, 180, 240, $480{\mu}mol/kg\;W^{0.75}$) with (+MCT) or without medium-chain triglycerides (-MCT) in 0.9% NaCl solution. Blood was sampled into heparinized tubes at 0, 1, 2, 4, 6, 8, 14, and 20 h after gavage, and urine was collected and pooled into 1 h or 2 h composite samples to determine free- and short-chain carnitine concentrations. Plasma from the 12 newborn piglets before gavage contained $10.6{\pm}1.2{\mu}mol/L$ free carnitine and $7.2{\pm}0.6{\mu}mol/L$ acid-soluble acyl carnitine. The renal threshold for carnitine was similar between the MCT and the +MCT group (42.6 13.1 and $46.4{\pm}2.0{\mu}mol/L$, respectively), but the correlation between plasma free carnitine and urinary excretion was altered. Plasma free carnitine linearly increased with increasing carnitine dosage (-MCT group, $R^2=0.95$, p<0.001; +MCT group, $R^2=0.91$, p<0.001), but was decreased by 50% when medium-chain triglycerides were fed. The peak in plasma free carnitine concentration was depressed by medium-chain triglycerides feeding also. Therefore, the plasma and urinary short-chain/free carnitine ratio of the +MCT group was increased by 100% and 40%, respectively (p<0.01). Feeding of medium-chain triglycerides may delay plasma carnitine elevation via altering the kinetics of absorption. Similarly, the plasma and urinary short-chain/free carnitine ratio were affected by interaction between medium-chain triglycerides and time (p<0.01). The present study suggests that an oral carnitine dose over $480{\mu}mol/kg\;W^{0.75}$ may be needed to reach the free carnitine renal threshold within a short period, especially when provided together with medium-chain triglyceride.

• Journal of Community Nutrition
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• v.4 no.2
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• pp.78-82
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• 2002

This study compared the effect of Korean vegetarian and omnivorous diets on plasma carnitine concentrations and urinary carnitine excretion. Twenty lactoovovegetarian and twenty omnivorous female college students consented to participate in this study. Daily nutritional intake and plasma and urinary nonesterified carnitine (NEC), acid-soluble acylcarnitine (ASAC), acid-insoluble acylcarnitine (AIAC), and total carnitine (TCNE) were determined. Daily protein, fat, retinol, vitamin B$_2$and vitamin B$\_$12/ intakes were significantly lower for vegetarians, however, fiber, carbohydrate, $\beta$-carotene, folic acid and vitamin C consumptions were much higher for vegetarians than omnivores. There were no differences in plasma NEC, ASAC, AIAC and TCNE concentrations between the two groups. Urinary carnitine excretion was lower in vegetarians, but only the differences in ASAC and TCNE excretions were statistically significant. These results suggest that the lower excretion of ASAC in vegetarians may be a reflection of their lipid metabolic state and that Korean vegetarian diets may accommodate lower carnitine intakes through efficient urinary conservation of carnitine.

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.181-187
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• 2009

Carnitine is known to be involved in lipid metabolism and affects body composition as well as energy metabolism of the whole body. Improvement of obesity by L-carnitine supplement suggests that obesity can be related with the abnormality of carnitine metabolism and therefore, plasma carnitine level in normal and obesity groups was investigated. For the characterization of plasma carnitine level in obese people, 60 plasma samples collected from Korean women subjects were analyzed using LC/MS and plasma fatty acid level was also determined using GC/MS. Additionally, several clinical chemical parameters including fasting glucose, cholesterol, AST, and ALT level were measured. All the data obtained were combined and pattern recognition analysis was carried out with the dataset. Obese group showed a different metabolic pattern compared with normal group. Plasma acylcarnitine level of the obese group was found to be $11.7{\mu}g/ml$, which was higher than that of normal group ($8.0{\mu}g/ml$). Statistically significant differences in plasma fatty acid level were not observed between the two groups. Other clinical parameters for the obese group were within normal ranges but AST and ALT levels were slightly elevated compared to normal group. The obese group showed elevated plasma acylcarnitine level.

• Nutritional Sciences
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• v.1 no.1
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• pp.56-60
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• 1998

The present study was conducted to find out whether there are some differences in plasma carnitine levels among young-, middle-, and old-aged normal Korean women. Daily food intake, body fat content, plasma lipids and carnitine levels were measured in 153 samples from 44 young (20-24 years old), 49 middle-aged (30-49 years old), and 63 old (65-85 years old) normal volunteers. The differences in concentrations of nonesterified acylcarnitine and acid-soluble acylcarnitine were not statistically significant among them. However, acid insoluble acylcarnitine (AIAC) level in plasma decreased with age. Moreover, total carnitine (TCNE) level in the young group was significantally higher than in old and middle-aged groups. Body fat content in the young group was significantly lower than in old and middle-aged groups. Plasma total cholesterol increased with age and triglycerides in the old group were significantly higher than in young and middle-aged groups. These results suggest that the higher levels of AIAC and TCNE in the young group may be a reflection of their lipid metabolic state, which is different from middle-aged and old groups.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.670-676
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• 1999

The effect of exercise and/or high fat diet on carnitine status and carnitine palmitoyltransferase I(CPT I) level were investigated in Weanling Sprague Dawley rats. The rats were fed an AIN 76 diet or a modified high fat AIN diet, supplemented with 35% corn oil, for 31 days. During the 31 day period half of the animals in each dietary group were exercised on a treadmill for 90 minutes per day. Carnitine concentrations were determined in plasma and liver and CPT I mRNA levels were measured by Northern blot analysis with CPT I cDNA probe in livers of rats. Exercise rats gained less weight than non exercised rats during the study for high fat diet group. Exercise rats had a higher plasma acid soluble acylcarnitine and acid insoluble acylcarnitine concnetrations than non exercised rats for normal diet group. Exercise or high fat diet increased liver carnitine concentration, but a mixed effect was not shown. In exercised rats, CPT I mRNA levels increased significantly relative to those of nonexercised rats. CPT I mRNA levels also increased when compared high fat fed rats with those of normal diet fed rats. These data suggest that there is a correlation between carnitine concen trations and CPT I mRNA levels and that CPT I can be regulated at the transcriptional level by exercise and/or high fat diet.

• Nutritional Sciences
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• v.8 no.2
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• pp.97-103
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• 2005

The goal of this study was to investigate abnotmalities in camitine metabolism present by determining blood camitine and lipid concentrations in Korean diabetic patients. The study subjects included 108 Korean diabetic patients (64 males and 44 females) who were hospitalized in Chonbuk National University Hospital and 27 subjects were also hospitalized as non-diabetic controls (10 males and 17 females). Glucose, total cholesterol, triglyceride (TG) and HDL-cholesterol in plasma were enzymatically assayed and insulin was measured by immunoradiometric assay. Nonesterified camitine (NEC), acid-soluble acylcarnitine (ASAC), and acid-insoluble acylcarnitine (AIAC) were determined by a modified radioisotopic method Glucose and insulin levels were significantly elevated in diabetic patients compared with controls. Total cholesterol was elevated in female but not male diabetic patients and triglycerides were elevated both in male and female diabetics. Plasma and urinary total carnitine (TCNE) were significantly elevated in diabetics as compared with normal controls. In male diabetics, NEC concentrations were significantly elevated above controls, but not in female subjects. Plasma NEC and TCNE concentrations were significantly increased in male diabetics, but significantly decreased in female diabetics. All urinary carnitine concentrations were significantly increased in diabetics as compared with controls. Urinary NEC concentrations were four times higher in male diabetics and three times higher in female diabetics than in controls. The ratios of serum and urinary acylcarnitine/NEC were also significantly higher in diabetics than in controls. This study suggested that there was a remarkable abnormality in lipid and carnitine metabolism in Korean diabetic patients, and the further study on carnitine metabolism and the effects of carnitine supplementation for Korean diabetic patients are needed.

• The Korean Journal of Zoology
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• v.32 no.4
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• pp.322-328
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• 1989

The effect of dietary carnitine on ethanol-induced fattv liver and hvpertriglyceridemia was examined in an animal model. Consistent with literature, ethanol fed at 5g/Kg of b.w. to rats produced a significant increase in hepatic concentrations of total lipid, kislycerine, phospholi-pid, free cholesterol and esteriaed cholesterol as well as elevated plasma concentrations of triglvceride. It was when the ethanol diet was supplemented with D.L. camitine that there was a singini-cant reduction in the accumulation of lipids in the ethanol-compromised liver. Dietary cacti-tine was also effective in ameliorating ethanol-induced hypeuriglyceridemia. Total protein con-tents in the plasma was not varied among the groups. Ethanol의 대사과정에 관여하는 영향중에 특징적인 것으로 과유지방혈증(hyperlipidemia) 까 지방간(fatty liver)을 거쳐 간경변에 이르는 간에 관계하는 일련의 증상들을 들 수 있다. 본 실험에서는 만성적 ethanol의 지방대사 장해에 대한 D.L.-carnitine의 효과에 대해 고찰하였다. 실험용 횐쥐를 사용하여 실험군(ethanol group)에게 체중 kg당 5g의 ethanol(30% in saline)을 투여하여 알콜유발성 지방간과 과유지방혈증을 일으키고, 그 실험군 흰쥐들에게 carnitine(0.4 mg/g of body weight)을 첨가하여 그 효과를 관찰하였다. 그 결과 carnitine을 첨가하여 투여한 흰쥐들에서 ethanol처리군과 비교하여 볼 때 간과 혈장에서 지방축적이 현저히 감소하는 것을 관찰할 수 있었다.

• Analytical Science and Technology
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• v.18 no.2
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• pp.163-167
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• 2005

In this study, a novel analytical method has been developed for the rapid determination of L-carnitine in human plasma using electrospray ionization tandem mass spectrometry. Free carnitine (FC) was analyzed after extraction with 80% methanol and total carnitine (TC) was analyzed after hydrolysis and extraction. Acyl carnitine (AC) was subtracted FC from TC. Analytical methods used multiple reaction monitoring (MRM) scan modes. A correlation coefficient of linear regression ($r^2$) was 0.9995, recovery was 97%, reproducibility was less than 10%, and limit of detection (LOD) was $0.0016{\mu}mol/L$. This method reduced sample preparation time and showed high resolution and good reproducibility compared to that with liquid chromatographic methods. Normal control showed AC was lower than FC. Clinical management of patients with inborn error of metabolism showed FC was lower than AC. Thus, carnitine fraction level was very important to monitoring patients with metabolic disorder.