Carnitine and deoxycarnitine concentration in rat tissues and urine after their administration

Metabolic Signatures of Life Span Regulated by Mating, Sex Peptide, and Mifepristone/RU486 in Female Drosophila melanogaster

Mating and transfer of male sex peptide (SP), or transgenic expression of SP, causes inflammation and decreased life span in female Drosophila. Mifepristone rescues these effects, yielding dramatic increases in life span. Here targeted metabolomics data were integrated with further analysis of extant transcriptomic data. Each of 7 genes positively correlated with life span were expressed in the brain or eye and involved regulation of gene expression and signaling. Genes negatively correlated with life span were preferentially expressed in midgut and involved protein degradation, amino acid metabolism, and immune response. Across all conditions, life span was positively correlated with muscle breakdown product 1/3-methylhistidine and purine breakdown product urate, and negatively correlated with tryptophan breakdown product kynurenic acid, suggesting a SP-induced shift from somatic maintenance/turnover pathways to the costly production of energy and lipids from dietary amino acids. Some limited overlap was observed between genes regulated by mifepristone and genes known to be regulated by ecdysone; however, mifepristone was unable to compete with ecdysone for activation of an ecdysone-responsive transgenic reporter. In contrast, genes regulated by mifepristone were highly enriched for genes regulated by juvenile hormone (JH), and mifepristone rescued the negative effect of JH analog methoprene on life span in adult virgin females. The data indicate that mifepristone increases life span and decreases inflammation in mated females by antagonizing JH signaling downstream of male SP. Finally, mifepristone increased life span of mated, but not unmated, Caenorhabditis elegans, in 2 of 3 trials, suggesting possible evolutionary conservation of mifepristone mechanisms.

Mitomycin C induces apoptosis via Fas/FasL dependent pathway and suppression of IL-18 in cervical carcinoma cells

Mitomycin C (MMC) is used fairly widely as an anticancer drug, as it possesses mechanisms of action which are preferable to other chemotherapeutic compounds, including cisplatin, docetaxel, and lovastatin. In the previous study, we established the RSV-luc promoter analysis system, which is used to screen drugs against cervical carcinomas caused by HPV infection. We then demonstrated the repression of HPV E6-activated RSV promoter activity by anticancer agents such as carboplatin (CA), cisplatin (CIS), and MMC. In these studies, we focused on the investigation of apoptotic mechanisms in MMC-treated cervical carcinoma cell lines, most notably SiHa/pRSV-luc (KCTC 0427BP) and SiHa. DNA fragmentation assays and TUNEL staining revealed that MMC and CIS, but not CA, resulted in apoptosis. MMC treatment induced a reduction in the expressions of the E6 oncogene and IL-18, in a p53-independent manner. MMC also increased FasL expression and induced the processing of caspases-8 and -3. Our results indicated that MMC induced apoptosis in SiHa/pRSV-luc and SiHa cells via caspase-8 and -3 processing, in a Fas/FasL-dependent manner. MMC also suppressed the expression of IL-18 in the same cells. MMC also down-regulated IkappaB expression, and up-regulated p65 expression. These results suggest that MMC induces apoptosis, not only through caspase-8 and -3 dependent Fas/FasL pathway, but also via the regulation of NF-kappaB activity and IL-18 expression.

Investigation of the effect of theophylline administration on total, free, short-chain acyl and long-chain acyl carnitine distributions in rat renal tissues

This study is conducted to investigate the effect of oral theophylline administration on total (TC), free (FC), short-(SC), long-chain acyl (LC), acyl (AC) carnitine distributions as well as the ratio of acyl to free carnitine (AC/FC) in rat renal tissues. Theophylline was administrated at 100 mg kg-1 body weight day-1, and effects were monitored after a treatment period that lasted between 1 week and 5 weeks. The results indicated that theophylline administration leads to significantly higher concentrations of TC, FC, SC, L and AC in renal tissues as compared to those of control and placebo groups (P < 0.001). Moreover, the ratio of AC/FC was significantly increased (P < 0.001) as compared to either control or placebo groups. These changes may result from theophylline-enhanced mobilization of lipids from adipose tissues, which consequently stimulates an increased carnitine transport into the renal tissues to form acylcarnitines for subsequent beta-oxidation inside the renal mitochondria.

Study of the effects of theophylline-related changes in total, free, short- chain acyl and long-chain acyl carnitine concentrations in rat heart

This study is conducted to investigate the effect of oral theophylline administration on total (TC), free (FC), short-(SC), long-chain acyl (LC), acyl (AC) carnitine concentrations and acyl to free carnitine (AC/FC) ratio in rat heart. Theophylline was administrated at 100 mg/kg wt/day, and effects were monitored after a treatment period that lasted between a week and five weeks. The results indicated that theophylline feeding leads to significantly higher concentrations of TC, FC, SC, LC and AC in heart tissue as compared to those of control and placebo groups (P < 0.001). Moreover, the ratio of AC/FC was significantly increased (P < 0.001) as compared to either control or placebo groups. These changes may result from theophylline-enhanced mobilization of lipids from adipose tissues, which consequently stimulates an increased carnitine transport into the heart tissues to form fatty acylcarnitines for subsequent beta-oxidation inside the heart mitochondria.

Determination of L-carnitine, acylcarnitine and total carnitine levels in plasma and tissues of camel (Camelus dromedarius)

The total, free and acyl carnitine levels were measured in plasma and tissues of the Arabian camel (Camelus dromedarius). Significant variation in carnitine concentrations were observed in plasma and tissues of the camel when compared with other animal species. A higher proportion of acyl carnitine was found in plasma and skeletal muscle of the camel than other animal species. Among the camel tissues, skeletal muscle possessed the highest amount of carnitine while the lowest amount was found in kidney. The higher carnitine content and a higher proportion of acyl carnitine in plasma and tissues of the Arabian camel suggest an adaptive mechanism that could be common to desert animal species.

Effect of carnitine feeding on the levels of heart and skeletal muscle carnitine of elderly mice

Aging has been associated with an increase in muscle dysfunction and weakness. We found a decrease in muscle carnitine with age [Biochem. Biophys. Res. Commun., 161 (1989) 1135-1143]. Prolonged oral administration to both young (2-month-old) and adult (7-month-old) mice with L-carnitine increased its content in blood by 50%. The levels of carnitine in skeletal and heart muscle of old treated animals became higher than in untreated mice of the same age. However, this extensive restoration did not reach the maximum values present in skeletal muscle of young mice. Our findings indicate that an alteration of the carnitine carrier in the sarcolemma could be responsible for the decrease with age of carnitine in skeletal but not in heart muscle.

Butyrobetaine is equal to L-carnitine in elevating L-carnitine levels in rats

This work shows that butyrobetaine administered to rats in a single dose can be highly effective in elevating L-carnitine levels in all tissues. This ability of butyrobetaine was compared to that of L-carnitine. In an experiment with tracer dose of the compounds, 12 h following administration of [3H]butyrobetaine plasma and tissues contained radioactivity exclusively in L-carnitine and in similar amounts as in the other group of animals receiving L-[3H]carnitine. This was observed both after intraperitoneal and oral administration of the compounds. In the loading experiments 100 mumol [3H]butyrobetaine was administered orally to one group and 100 mumol L-[3H]carnitine to the other group of animals and 12 h later it was found that butyrobetaine caused the same increments in L-carnitine as L-carnitine administration. The increments in the organs of the butyrobetaine-treated group (in decreasing order) were as follows: kidney, 1227 nmol/g vs. 652 nmol/g; liver, 469 nmol/g vs. 258 nmol/g; muscle, 1043 nmol/g vs. 881 nmol/g; plasma, 79.4 nmol/ml vs. 39.3 nmol/ml. Butyrobetaine (100 mumol) caused similar increments when it was administered intraperitoneally. Based on these results butyrobetaine can be considered as a potential agent for L-carnitine supplementation therapy.

Effect of exogenous carnitine on carnitine homeostasis in the rat

The interaction of exogenous carnitine with whole body carnitine homeostasis was characterized in the rat. Carnitine was administered in pharmacologic doses (0-33.3 mumols/100 g body weight) by bolus, intravenous injection, and plasma, urine, liver, skeletal muscle and heart content of carnitine and acylcarnitines quantitated over a 48 h period. Pre-injection urinary carnitine excretion was circadian as excretion rates were increased 2-fold during the lights-off cycle as compared with the lights-on cycle. Following carnitine administration, there was an increase in urinary total carnitine excretion which accounted for approx. 60% of the administered carnitine at doses above 8.3 mumols/100 g body weight. Urinary acylcarnitine excretion was increased following carnitine administration in a dose-dependent fashion. During the 24 h following administration of 16.7 mumols [14C]carnitine/100 g body weight, urinary carnitine specific activity averaged only 72 +/- 4% of the injection solution specific activity. This dilution of the [14C]carnitine specific activity suggests that endogenous carnitine contributed to the increased net urinary carnitine excretion following carnitine administration. 5 min after administration of 16.7 mumol carnitine/100 g body weight approx. 80% of the injected carnitine was in the extracellular fluid compartment and 5% in the liver. Plasma, liver and soleus total carnitine contents were increased 6 h after administration of 16.7 mumols carnitine/100 g body weight. 6 h post-administration, 37% of the dose was recovered in the urine, 12% remained in the extracellular compartment, 9% was in the liver and 22% was distributed in the skeletal muscle. In liver and plasma, short chain acylcarnitine content was increased 5 min and 6 h post injection as compared with controls. Plasma, liver, skeletal muscle and heart carnitine contents were not different from control levels 48 h after carnitine administration. The results demonstrate that single, bolus administration of carnitine is effective in increasing urinary acylcarnitine elimination. While liver carnitine content is doubled for at least 6 h following carnitine administration, skeletal muscle and heart carnitine pools are only modestly perturbed following a single intravenous carnitine dose. The dilution of [14C]carnitine specific activity in the urine of treated animals suggests that tissue-blood carnitine or acylcarnitine exchange systems contribute to overall carnitine homeostasis following carnitine administration.