Diosgenin prevents dexamethasone-induced myotube atrophy in C2C12 cells.

Several pathophysiological abnormalities, including a sedentary lifestyle, chronic diseases, and oxidative stress, can contribute to muscle atrophy triggered by an imbalance in muscle protein synthesis and degradation. Resolving muscle atrophy is a critical issue as it can reduce the quality of life. Here, one of the promising functional food factors, diosgenin (a steroidal sapogenin) showed strong preventive activities against dexamethasone (Dex)-induced muscle atrophy, as determined by the expression levels and morphology of the myosin heavy chain in C2C12 myotubes. Diosgenin inhibited protein expressions of Dex-induced skeletal muscle-specific ubiquitin ligase, including muscle RING finger 1 (MuRF1) and casitas B-lineage lymphoma protooncogene b (Cbl-b) but not atrogin-1. Diosgenin ameliorated Dex-induced declines of Akt phosphorylation at Ser473 and FoxO3a phosphorylation at Ser253, which probably at least partially contributed to the suppression of MuRF1, Cbl-b, and atrogin-1 gene expression. Additionally, diosgenin inhibited Dex-induced nuclear translocation of the glucocorticoid receptor (GR), diosgenin therefore may competitively inhibit the interaction between Dex and GR. These findings suggest that diosgenin is an effective functional food for preventing glucocorticoid-induced skeletal muscle atrophy.

Theophylline Prevents Dexamethasone-Induced Atrophy in C2C12 Myotubes.

Skeletal muscle mass is maintained by a balance between the synthesis and degradation of muscle proteins, the collapse of which causes muscle wasting. The prevention of muscle wasting improves the quality of life and extends a healthy life. The methyl xanthine theophylline showed strong preventive activity against dexamethasone-induced muscle atrophy, as determined using the expression level of myosin heavy chain in C2C12 myotubes. Mechanistically, theophylline inhibited the expression of ubiquitin ligases MuRF1 and Cbl-b, but not that of atrogin-1. Furthermore, theophylline inhibits glucocorticoid receptor translocation to the nucleus. A pull-down assay using a theophylline probe revealed that theophylline and dexamethasone competitively interacted with the glucocorticoid receptor, suggesting an antagonistic activity of theophylline on glucocorticoid receptors. Additionally, theophylline inhibited the dexamethasone-induced phosphorylation of p38 and FoxO3a in C2C12 myotubes. These findings suggest that theophylline is an effective food ingredient in the prevention of glucocorticoid-induced skeletal muscle atrophy.

Nutritional Factors That Affect the Formation of 5-Aminolevulinic Acid, a Key Intermediate of Heme Biosynthesis.

5-Aminolevulinic acid (ALA) is a key intermediate of heme biosynthesis, which is an essential component of the respiratory chain. Therefore, nutrients that affect ALA biosynthesis eventually affect ATP production, which is the basis of mitochondrial function. Although the effects of various non-nutrient components that affect ALA after biosynthesis have been reported, there are few reports on the effects of dietary amino acids/protein on ALA formation and the effects of dietary vitamins that are involved in amino acid metabolism. In mitochondria, ALA is synthesized from succinyl-CoA and glycine by the pyridoxal phosphate-dependent enzyme ALA synthase [EC 2.3.1.37]. In this study, the effects of dietary amino acids/protein and vitamins on the amount of ALA synthesized were investigated using mice, rats, and cultured cells. Amounts of ALA in plasma and urine, and porphyrins in plasma increased with increasing protein intake. Vitamin B1 insufficiency did not affect ALA synthesis. Vitamin B6 insufficiency increased the amount of ALA synthesized, while niacin deficiency markedly reduced ALA synthesis. Thus, for heme synthesis, an essential biological substance for life, the amounts of amino acids, as well as the pathways metabolizing amino acids to glycine and succinyl-CoA are very important. Specifically, it is important that niacin is associated with the formation of glycine and succinyl-CoA from amino acids.

Effects of B-Group Vitamin Administration on Daily Change in Urine 2-Oxo Acids in Young Japanese Women.

B-group vitamins are required in amino acid catabolism, and recent findings suggest that urine 2-oxo acids, catabolites of amino acid, could be functional biomarkers indicating the nutritional status of B-group vitamins. To clarify the relationship between B-group vitamins and urine 2-oxo acids, we investigated the effects of B-group vitamin administration on daily changes in urinary amounts of 2-oxo acids in humans. Twenty-nine young Japanese women collected 24-h urine samples for 8 d, and took B-group vitamins for 7 d beginning on the second day of urine collection. The participants were divided into three groups on the basis of the amounts of total branched-chain 2-oxo acids, 2-oxoglutaric acid, 2-oxoadipic acid, and pyruvic acid excreted in urine. In the upper tertile, but not the middle and lower tertiles, each urine 2-oxo acid decreased from the first day of vitamin administration, and completely decreased to a normal level on the second day of administration. These results indicate that administration of B-group vitamins immediately affects 2-oxo acid metabolism in some young Japanese women. Thus, urinary 2-oxo acids could be useful and functional biomarkers for B-group vitamin status.

Blood concentrations and renal clearance of water-soluble vitamins in outpatients with ulcerative colitis.

Few studies have investigated the association between dietary intake and blood concentrations of water-soluble vitamins in patients with ulcerative colitis (UC). In the present study, vitamin concentrations were measured in the blood and urinary excretion of 23 outpatients with UC and compared against a control group of 20 healthy participants. A weighed food record procedure was used to ensure controlled macronutrient and vitamin intakes of the UC cohort. Individuals in the control group were given a semi-purified diet for 8 days prior to assessment. Multiple linear regression analysis was used to identify important differences in vitamin concentrations, independent of sex, age and other confounding variables. The blood concentrations of vitamins B2, C, niacin and folate were markedly lower in the patients with UC than those in the control group, and the renal clearance of vitamins B1, B6, B12 and folate was notably higher in the UC cohort. It was concluded that vitamins B2, C, niacin and folate were at significantly lower concentrations in patients with UC following adjustment for coexisting factors. The lower levels of niacin may be partially due to impaired reabsorption. Chronic inflammation, common in patients with UC, with may contribute to the lower levels of other vitamins by rendering amino acid and carbohydrate metabolism into a hypermetabolic state. As the role of vitamins in metabolic activity is constant and pervasive, nutritional management including the application of water-soluble vitamins appears important for patients suffering from UC.

Urinary Excretion of 2-Oxo Acids Is Greater in Rats with Streptozotocin-Induced Diabetes.

2-Oxo acids derived from amino acids, glucose, and fatty acids are key intermediates in energy production. During diabetes, energy production is known to be lower than in healthy individuals. However, it was unknown whether the production of 2-oxo acids is impacted by diabetes. In the present study, I compared the quantities of 2-oxo acids (pyruvic acid, oxaloacetic acid, 2-oxoglutaric acid, 2-oxoadipic acid, 2-oxoisovaleric acid, 2-oxo-3-methylvaleric acid, and 2-oxo-4-methylvaleric acid) excreted in the urine of normoglycemic control rats and rats with streptozotocin-induced diabetes, which reflect the quantities of unused 2-oxo acids in the body. Greater urinary excretion of unused 2-oxo acids thus implies an impairment in energy production. The respective quantities of urinary pyruvic acid + oxaloacetic acid (measured together), 2-oxoglutaric acid, 2-oxoadipic acid, 2-oxoisovaleric acid, 2-oxo-3-methylvaleric acid, and 2-oxo-4-methylvaleric acid in the diabetic rats were 2.0- (p<0.0001), 2.5- (p<0.0001), 1.5- (p=0.008), 7.6- (p<0.0001), 6.1- (p<0.0001), and 2.1-fold (p<0.0001) greater than in the control rats per 1 g food intake. Thus, the biggest differences were observed in 2-oxoisovaleric acid (a catabolite of valine) and 2-oxo-3-methylvaleric acid (a catabolite of isoleucine). These findings indicate that energy production in the body is suppressed under diabetic conditions.

Organ Co-Relationship in Tryptophan Metabolism and Factors That Govern the Biosynthesis of Nicotinamide from Tryptophan.

The pathway of tryptophan (Trp)-nicotinamide is very important nutritionally because a vitamin nicotinamide is biosynthesized from an amino acid Trp. Until we started studying the factors that affect the Trp-nicotinamide conversion rate, little data existed. Data obtained from TDO (Trp 2,3-dioxygenase)-KO (knock-out) mice have revealed that mice can biosynthesize a necessary amount of nicotinamide from Trp by indoleamine 2,3-dioxygenase (IDO) even when TDO is lacking. It has also been shown that 3-hydroxyanthranilic acid is a key intermediate. Urine upper metabolites such as kynurenic acid and xanthurenic acid originate from non-hepatic tissues but not from the liver. Data obtained from quinolinic acid phosphoribosyltransferase (QPRT)-KO mice indicated that the Trp→quinolinic acid conversion ratio was 6%. Urine quinolinic acid levels and the conversion ratio of Trp to nicotinamide were the same between hetero and wild mice. These findings indicate that QPRT is not the rate-limiting enzyme in the conversion. Thus, the limiting factors in the conversion of Trp to nicotinamide are the amounts of 3-hydroxyanthranilic acid and quinolinic acid in the liver and the activity of liver 3-hydroxyanthranilic acid 3,4-dioxygenase. Studies on factors have shown that conversion of Trp to nicotinamide is increased by adequate intake of good quality protein, and adequate intake of unsaturated fatty acids and starch. However, conversion was decreased by deficient niacin, vitamin B2, or vitamin B6, excessive intake of protein, saturated fatty acids, or glucose and fructose, or intake of protein with low Trp content, and insufficient mineral intake.

Oral Glucose Tolerance and Tryptophan Metabolism in Non-Obese and Non-Insulin-Dependent Diabetic Goto-Kakizaki Rats Fed High-Tryptophan Diets.

We investigated oral glucose tolerance and tryptophan (Trp) metabolism in non-obese and non-insulin-dependent diabetic Goto-Kakizaki (GK) rats fed high-Trp diets. Five-week-old male Wistar and GK rats were fed a 20% casein diet (control diet) or the same diet supplemented with 1%, 2%, 3%, or 5% Trp for 58 d. Oral glucose tolerance tests were performed on Days 14 and 28 of the experimental period. Urine as well as livers and blood were collected on the last day of the experiment. The glucose concentration and the amount of Trp metabolites were measured. On Day 14 of the experiment, the incremental blood glucose concentrations integrated over a period of 2 h (ΔAUC0-2h) of blood glucose in rats fed the 3% and 5% Trp diets had decreased by 13% and 18%, respectively, compared with that of the control-GK rats. However, no significant differences were found in the rats fed +1% or +2% Trp diets compared with control-GK rats. On Day 28, there were no significant differences found in the ΔAUC0-2h of blood glucose levels in any group including the control-GK group. On the last day, the concentrations of plasma glucose, total cholesterol, and triglyceride did not show differences in any group. There were no specific phenomena observed in the metabolism of Trp in GK rats even when fed an excess of Trp, compared with that of Wistar rats. Oral Trp administration and its continuous use may not improve blood glucose levels in type 2 diabetic rats.

A Suitable Diet for Recovery from Starvation Is a High-Fat Diet, but Not a High-Protein Diet, in Rats.

The present study aims to determine the most suitable dietary balance of energy-producing nutrients for recovery from starvation. Rats were fed their standard high- carbohydrate diet (HCD, carbohydrate energy : protein energy : fat energy=71 : 18 : 11) for 7 d and then deprived of food for 3 d (short-term starvation) or 8 d (long-term starvation). The starved rats were then fed the HCD, a high-protein diet (HPD, 31 : 57 : 12), or a high-fat diet (HFD, 34 : 14 : 52) for 8 d. Rats had ad libitum access to drinking water throughout the experimental period, including the starvation period. The reference group was allowed free access to the HCD throughout the experimental period. Characteristically, increased drinking, increased urea nitrogen in the plasma and urine, and hypertrophy of the kidneys, were observed in the HPD group. Furthermore, the recovery of plasma glucose level was insufficient in this group. Therefore, administration of a HPD was contraindicated in recovery from starvation. The recovery of body weight after starvation was excellent in the HFD group. No effect on the metabolism of B-group vitamins involved in energy metabolism was found with the administration of any diet. The effects of HCD and HFD administration on recovery from starvation were investigated in further detail. No adverse effects were observed on the tissue to body weight mass ratios or biochemical parameters in blood in the HFD group. From the above findings, it is hypothesized that a HFD is most suitable for quickly reversing the influence of starvation.

Thirteen week toxicity study of dietary l-tryptophan in rats with a recovery period of 5 weeks.

Although l-tryptophan is nutritionally important and widely used in medical applications, toxicity data for its oral administration are limited. The purpose of this study was to evaluate the potential toxicity of an experimental diet containing added l-tryptophan at doses of 0 (basal diet), 1.25%, 2.5% and 5.0% when administered to Sprague-Dawley rats for 13 weeks. There were no toxicological changes in clinical signs, ophthalmology, urinalysis, hematology, necropsy, organ weight and histopathology between control rats and those fed additional l-tryptophan. Body weight gain and food consumption significantly decreased throughout the administration period in males in the 2.5% group and in both sexes in the 5.0% group. At the end of the dosing period, decreases in water intake in males in the 5.0% group and in serum glucose in females in the 5.0% group were observed. The changes described above were considered toxicologically significant; however, they were not observed after a 5 week recovery period, suggesting reversibility. Consequently, the no-observed-adverse-effect level of l-tryptophan in the present study was 1.25% for males and 2.5% for females (mean intake of l-tryptophan: 779 mg kg-1 body weight day-1 [males] and 1765 mg kg-1 body weight day-1 [females]). As the basal diet used in this study contained 0.27% of proteinaceous l-tryptophan, the no-observed-adverse-effect level of overall l-tryptophan was 1.52% for males and 2.77% for females (mean intake of overall l-tryptophan: 948 mg kg-1 body weight day-1 (males) and 1956 mg kg-1 body weight day-1 (females)). We conclude that l-tryptophan has a low toxicity profile in terms of human use.

High-dose thiamine prevents brain lesions and prolongs survival of Slc19a3-deficient mice.

SLC19A3 deficiency, also called thiamine metabolism dysfunction syndrome-2 (THMD2; OMIM 607483), is an autosomal recessive neurodegenerative disorder caused by mutations in SLC19A3, the gene encoding thiamine transporter 2. To investigate the molecular mechanisms of neurodegeneration in SLC19A3 deficiency and whether administration of high-dose thiamine prevents neurodegeneration, we generated homozygous Slc19a3 E314Q knock-in (KI) mice harboring the mutation corresponding to the human SLC19A3 E320Q, which is associated with the severe form of THMD2. Homozygous KI mice and previously reported homozygous Slc19a3 knock-out (KO) mice fed a thiamine-restricted diet (thiamine: 0.60 mg/100 g food) died within 30 and 12 days, respectively, with dramatically decreased thiamine concentration in the blood and brain, acute neurodegeneration, and astrogliosis in the submedial nucleus of the thalamus and ventral anterior-lateral complex of the thalamus. These findings may bear some features of thiamine-deficient mice generated by pyrithiamine injection and a thiamine-deficient diet, suggesting that the primary cause of THMD2 could be thiamine pyrophosphate (TPP) deficiency. Next, we analyzed the therapeutic effects of high-dose thiamine treatment. When the diet was reverted to a conventional diet (thiamine: 1.71 mg/100 g food) after thiamine restriction, all homozygous KO mice died. In contrast, when the diet was changed to a high-thiamine diet (thiamine: 8.50 mg/100 g food) after thiamine restriction, more than half of homozygous KO mice survived, without progression of brain lesions. Unexpectedly, when the high-thiamine diet of recovered mice was reverted to a conventional diet, some homozygous KO mice died. These results showed that acute neurodegeneration caused by thiamine deficiency is preventable in most parts, and prompt high-dose thiamine administration is critical for the treatment of THMD2. However, reduction of thiamine should be performed carefully to prevent recurrence after recovery of the disease.

Effects of Mild and Severe Vitamin B1 Deficiencies on the Meiotic Maturation of Mice Oocytes.

We investigated the effects of vitamin B1 deficiency on the meiosis maturation of oocytes. Female Crl:CD1 (ICR) mice were fed a 20% casein diet (control group) or a vitamin B1-free diet (test group). The vitamin B1 concentration in ovary was approximately 30% lower in the test group than in the control group. Oocyte meiosis was not affected by vitamin B1 deficiency when the deficiency was not accompanied by body weight loss. On the contrary, frequency of abnormal oocyte was increased by vitamin B1 deficiency when deficiency was accompanied by body weight loss (referred to as severe vitamin B1 deficiency; frequency of abnormal oocyte, 13.8% vs 43.7%, P = .0071). The frequency of abnormal oocytes was decreased by refeeding of a vitamin B1-containing diet (13.9% vs 22.9%, P = .503). These results suggest that severe vitamin B1 deficiency inhibited meiotic maturation of oocytes but did not damage immature oocytes.

Concentrations of Water-Soluble Vitamins in Blood and Urinary Excretion in Patients with Diabetes Mellitus.

We examined the concentrations of water-soluble vitamins in blood and urinary excretion of 22 patients with type 2 diabetes mellitus (type 2DM) and 20 healthy control participants. Macronutrient and vitamin intakes of type 2DM subjects were measured using a weighed food record method. Control participants consumed a semipurified diet for eight days. Multiple linear regression models were used to determine whether significant differences existed in vitamin concentrations in blood independent of age, sex, and other confounding factors. Concentrations of vitamins B2, B6, C, niacin, and folate in blood were significantly lower in type 2DM subjects than in controls, independent of confounding factors. Renal clearances of vitamins B6, C, niacin, and folate were significantly higher in type 2DM subjects than in controls. In conclusion, concentrations of vitamins B2, B6, C, niacin, and folate in blood were significantly lower in type 2DM subjects than in controls, independent of confounding factors; based on the evidence of increased urinary clearance of these vitamins, the lower levels were likely due to impaired reabsorption processes.

Urinary Branched-Chain 2-Oxo Acids as a Biomarker for Function of B-Group Vitamins in Humans.

To find a functional biomarker of B-group vitamins, we collected 24-h urine samples from young Japanese women who lived in the community (n=29) to measure branched-chain 2-oxo acids such as 2-oxo-3-methylbutanoic acid, 2-oxo-3-methylpentanoic acid, and 2-oxo-4-methylpentanoic acid because B-group vitamins are involved in the catabolism of branched-chain amino acids. The relationships between each pair of the three urinary 2-oxo acids were very high (2-oxo-3-methylbutanoic acid and 2-oxo-3-methylpentanoic acid, p<0.001; 2-oxo-3-methylbutanoic acid and 2-oxo-4-methylpentanoic acid, p<0.001; 2-oxo-3-methylpentanoic acid and 2-oxo-4-methylpentanoic acid, p<0.001). The participants were divided into three groups using the upper (n=10), middle (n=9), and lower tertiles (n=10) based on the urinary excretion amounts of the sum of the three branched-chain 2-oxo acids. The administration of capsules containing the daily necessary amounts of B-group vitamins led to a decrease in the urinary excretion of the sum of the three types of branched-chain 2-oxo acids in participants belonging to the upper tertile. A similar phenomenon was observed in the middle tertile, but not in the lower tertile. Intakes of B-group vitamins and the urinary excretion amounts of B-group vitamins were not observed to be significantly different among the upper, middle, and lower tertiles. These results indicate that some young Japanese women need much higher levels of B-group vitamins than the Dietary Reference Intakes for Japanese. Thus, urinary branched-chain 2-oxo acids are useful functional biomarkers for B-group vitamins in humans.

ß-Nicotinamide Mononucleotide, an Anti-Aging Candidate Compound, Is Retained in the Body for Longer than Nicotinamide in Rats.

The turnover of the oxidized form of nicotinamide adenine dinucleotide (NAD+) has attracted interest in regard to longevity. Thus, compounds that can rapidly increase the cellular NAD+ concentration have been surveyed by many researchers. Of those, ß-nicotinamide mononucleotide (ß-NMN) has been focused on. Studies on the biosynthesis of NAD+ from ß-NMN have been reported at the cellular level, but not at the whole animal level. In the present study, we investigated whether ß-NMN is superior to nicotinamide (Nam) as a precursor of NAD+ in whole animal experiments. To this end we compared the NAD+ concentration in the blood and the urinary excretion amounts of NAD+ catabolites. Rats were intraperitoneally injected with ß-NMN or Nam. After the injection, blood samples and urine samples were collected at 3-h intervals. The concentration of blood total NAD (NAD11NADH) in each sample showed no significant differences between the two groups. The urinary excretion amounts of NAD+ catabolites in the urine samples collected at 3-6 h after the injection were lower in the ß-NMN group than in the Nam group. These results suggest that ß-NMN is retained in the body for longer than Nam.

Urinary excretion ratio of xanthurenic acid/kynurenic acid as a functional biomarker of niacin nutritional status.

The present study was conducted to survey functional biomarkers for evaluation of niacin nutritional status. Over 500 enzymes require niacin as a coenzyme. Of these, we chose the tryptophan degradation pathway. To create niacin-deficient animals, quinolinic acid phosphoribosyltransferase-knock out mice were used in the present study because wild type mice can synthesize nicotinamide from tryptophan. When the mice were made niacin-deficient, the urinary excretion of xanthurenic acid (XA) was extremely low compared with control mice; however, it increased according to the recovery of niacin nutritional status. The urinary excretion of kynurenic acid (KA) was the reverse of XA. Kynurenine 3-monooxygenase, which needs NADPH, was thought to be suppressed by niacin deficiency. Thus, we calculated the urinary excretion ratio of XA:KA as a functional biomarker of niacin nutrition. The ratio increased according to recovering niacin nutritional status. Low values equate with low niacin nutritional status.

Organ Correlation with Tryptophan Metabolism Obtained by Analyses of TDO-KO and QPRT-KO Mice.

The aim of this article is to report the organ-specific correlation with tryptophan (Trp) metabolism obtained by analyses of tryptophan 2,3-dioxygenase knockout (TDO-KO) and quinolinic acid phosphoribosyltransferase knockout (QPRT-KO) mice models. We found that TDO-KO mice could biosynthesize the necessary amount of nicotinamide (Nam) from Trp, resulting in the production of key intermediate, 3-hydroxyanthranilic acid. Upstream metabolites, such as kynurenic acid and xanthurenic acid, in the urine were originated from nonhepatic tissues, and not from the liver. In QPRT-KO mice, the Trp to quinolinic acid conversion ratio was 6%; this value was higher than expected. Furthermore, we found that QPRT activity in hetero mice was half of that in wild-type (WT) mice. Urine quinolinic acid levels remain unchanged in both hetero and WT mice, and the conversion ratio of Trp to Nam was also unaffected. Collectively, these findings show that QPRT was not the rate-limiting enzyme in the conversion. In conclusion, the limiting factors in the conversion of Trp to Nam are the substrate amounts of 3-hydroxyanthranilic acid and activity of 3-hydroxyanthranilic acid 3,4-dioxygenase in the liver.

High-performance liquid chromatographic method for profiling 2-oxo acids in urine and its application in evaluating vitamin status in rats.

B-group vitamins are involved in the catabolism of 2-oxo acids. To identify the functional biomarkers of B-group vitamins, we developed a high-performance liquid chromatographic method for profiling 2-oxo acids in urine and applied this method to urine samples from rats deficient in vitamins B1 and B6 and pantothenic acid. 2-Oxo acids were reacted with 1,2-diamino-4,5-methylenebenzene to produce fluorescent derivatives, which were then separated using a TSKgel ODS-80Ts column with 30 mmol/L of KH2PO4 (pH 3.0):acetonitrile (7:3) at a flow rate of 1.0 mL/min. Vitamin B1 deficiency increased urinary levels of all 2-oxo acids, while vitamin B6 deficiency only increased levels of sum of 2-oxaloacetic acid and pyruvic acid, and pantothenic acid deficiency only increased levels of 2-oxoisovaleric acid. Profiles of 2-oxo acids in urine samples might be a non-invasive way of clarifying the functional biomarker of B-group vitamins.

Folic Acid Deficiency Does Not Adversely Affect Oocyte Meiosis in Mice.

Spindle defect and chromosome misalignment occuring in oocyte meiosis induce nondisjunction. Nondisjunction causes Down syndrome, also known as trisomy 21. Folic acid (FA) is an essential nutrient composition for fetal growth and development. It has been reported that FA nutritional status is associated with the risk of Down syndrome. However, to our knowledge, little is known about the effect of FA deficiency on abnormal oocytes (spindle defects, chromosome misalignments and immature oocyte) in vivo. In the present study, we investigate the effects of FA deficiency on oocyte meiosis in female mice. In order to induce FA deficiency in mice, female Crl:CD1 mice were fed a FA-free diet for 58 d. The diet also contained an antibiotic which has functions on limiting FA formation by intestinal microorganisms. The level of FA deficiency was determined by measuring the concentration of FA in the liver, hemocyte, uterus, ovary, and urine. FA concentrations in these samples from the FA-deficient group were 50-90% lower. Despite this, the frequency of abnormal oocytes was no different between the FA-deficient and control groups (20.0% vs 14.6%). According to the past research, FA transporter was strongly expressed in oocytes. Hence, it is possible that FA-free diets may not affect the concentration of oocyte FA in mice. To sum up these data, our study concluded that FA deficiency did not adversely affect oocyte meiosis.

Effects of Fatty Liver Induced by Excess Orotic Acid on B-Group Vitamin Concentrations of Liver, Blood, and Urine in Rats.

Fatty liver is caused when rats are given orotic acid of the pyrimidine base in large quantities. The lack of B-group vitamins suppresses the biosynthesis of fatty acids. We investigated how orotic acid-induced fatty liver affects the concentrations of liver, blood, and urine B-group vitamins in rats. The vitamin B6 and B12 concentrations of liver, blood, and urine were not affected by orotic acid-induced fatty liver. Vitamin B2 was measured only in the urine, but was unchanged. The liver, blood, and urine concentrations of niacin and its metabolites fell dramatically. Niacin and its metabolites in the liver, blood, and urine were affected as expected. Although the concentrations of vitamin B1, pantothenic acid, folate, and biotin in liver and blood were decreased by orotic acid-induced fatty liver, these urinary excretion amounts showed a specific pattern toward increase. Generally, as for the typical urinary excretion of B-group vitamins, these are excreted when the body is saturated. However, the ability to sustain vitamin B1, pantothenic acid, folate, and biotin decreased in fatty liver, which is hypothesized as a specific phenomenon. This metabolic response might occur to prevent an abnormally increased biosynthesis of fatty acids by orotic acid.