It is well known that biotin deficiency causes morphological anomalies in hatchlings of fowl. An abundance of biotin in the yolk, therefore, is greatly required for maintaining reproductive functions. Although there is growing evidence for the molecular significance of the vitamin in the processes of the reproductive system in mammals, little is known about its use and roles in fowl's yolk. This review focuses on studies on the roles of biotin in the ovarian follicles and embryos of domestic fowl. Recent studies from our laboratory showed an analysis of the mechanism of biotin supply from the maternal body to follicles, or the yolk using the eggs of domestic fowl. In growing ovarian follicles, biotin was incorporated into the follicles, particularly in a large amount immediately before ovulation. Biotin incorporated from the early stage to the growth stage of ovarian follicles was stored in the protein-binding form and became free biotin again immediately before ovulation. This may be because the biotin necessary for the maintenance of embryonic growth and development should be used immediately after fertilization. In embryos, free biotin in the yolk increased shortly after fertilization. A large amount of free biotin was incorporated into the embryo at the age of 3-4 d. Biotin supply to the embryo differed among embryonic growth stages and organs, suggesting involvement in the formation of each tissue and organ. Thus, a large amount of biotin was utilized for embryonic growth, suggesting its important role in normal embryonic growth. These findings show that biotin is an essential nutrient and may play a major role in the normal morphogenesis of embryos in domestic fowl.
Several reports indicate an important role for vitamin K in bone health as well as blood coagulation. However, the current Adequate Intakes (AI) might not be sufficient for the maintenance of bone health. To obtain a closer estimate of dietary intake of phylloquinone (PK) and menaquinones (MKs), PK, MK-4 and MK-7 contents in food samples (58 food items) were determined by an improved high-performance liquid chromatography method. Next, we assessed dietary vitamin K intake in young women living in eastern Japan using vitamin K contents measured here and the Standard Tables of Food Composition in Japan. PK was widely distributed in green vegetables and algae, and high amounts were found in spinach and broccoli (raw, 498 and 307 μg/100 g wet weight, respectively). Although MK-4 was widely distributed in animal products, overall MK-4 content was lower than PK. MK-7 was observed characteristically in fermented soybean products such as natto (939 μg/100 g). The mean total vitamin K intake of all subjects (using data from this study and Japanese food composition tables) was about 230 μg/d and 94% of participants met the AI of vitamin K for women aged 18-29 y in Japan, 60 μg/d. The contributions of PK, MK-4 and MK-7 to total vitamin K intake were 67.7, 7.3 and 24.9%, respectively. PK from vegetables and algae and MK-7 from pulses (including fermented soybean foods) were the major contributors to the total vitamin K intake of young women living in eastern Japan.
A marine eukaryotic microorganism, Schizochytrium limacinum SR21, had the ability to absorb and accumulate exogenous cobalamin, which was converted to the cobalamin coenzymes 5'-deoxyadenosylcobalamin (20.1%) and methylcobalamin (29.6%). A considerably high activity (about 38 mU/mg protein) of 5'-deoxyadenosylcobalamin-dependent methylmalonyl-CoA mutase (EC 126.96.36.199) involved in amino acid and odd-chain fatty acid metabolism was found in the cell homogenate of S. limacinum SR21. The enzyme was purified to homogeneity and characterized.
The effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance was investigated in aged mice. Fifty three-week-old male Crlj:CD-1 (ICR) mice were fed one of three experimental diets containing either 6% lard, 6% fish oil, or 6% sea snake lipids for 16 wk. The swimming exercise was carried out in an acrylic plastic tank filled with 25 cm of water maintained at 23oC. Swimming times to exhaustion were measured with a load of 2% of their body weights attached to the tails of the mice. The swimming times to exhaustion of the group that were fed the sea snake lipid diet tended to be longer than those of the lard diet group, and were significantly improved compared with the fish oil diet group (p<0.05). The plasma and muscle lactate levels were significantly lower in the sea snake lipid diet group than in the lard and fish oil diet groups (p<0.05). The liver glycogen and plasma glucose levels of the sea snake lipid diet group did not differ markedly from those of the lard diet group (p>0.05), and were significantly higher than those of the fish oil diet group (p<0.05). These results suggest that an intake of sea snake lipids but not the fish oil, which is also rich in n-3 polyunsaturated fatty acids (n-3 PUFAs), is useful for improving the swimming endurance of aged mice by attenuating lactate production and/or enhancing lactate clearance during swimming exercise, and the n-3 PUFAs contained in the sea snake lipids did little or nothing for this improved endurance.
Momordica charantia (bitter melon) is commonly known as vegetable insulin, but the mechanisms underlying its hypoglycemic effect remain unclear. To address this issue, the effects of bitter melon extracts on postprandial glycemic responses have been investigated in rats. An aqueous extract (AE), methanol fraction (MF) and methanol insoluble fraction (MIF) were prepared from bitter melon. An oral sucrose tolerance test revealed that administration of AE, MF or MIF each significantly suppressed plasma glucose levels at 30 min as compared with the control. In addition, the plasma insulin level at 30 min was also significantly lower after MF administration than in the control in the oral sucrose tolerance test. By contrast, these effects of bitter melon extracts were not observed in the oral glucose tolerance test. In terms of mechanism, bitter melon extracts dose-dependently inhibited the sucrase activity of intestinal mucosa with IC50 values of 8.3, 3.7 and 12.0 mg/mL for AE, MF and MIF, respectively. The fraction with a molecular weight of less than 1,300 (LT 1,300) obtained from MF inhibited the sucrase activity most strongly in an uncompetitive manner with an IC50 value of 2.6 mg/mL. Taken together, these results demonstrated that bitter melon suppressed postprandial hyperglycemia by inhibition of α-glucosidase activity and that the most beneficial component is present in the LT 1,300 fraction obtained from MF.
Liver tyrosine aminotransferase (TAT) activity is known to increase with ethanol treatment; however, the mechanism of this increase is unclear. Upon investigation we found that TAT activity and mRNA levels started to increase 2 h after ethanol administration and continued to increase until 6 h after ethanol administration. The increase in ethanol-induced TAT activity could not be explained by calorie loading after fasting, since ethanol loading increased TAT expression, while glucose loading decreased TAT expression. In addition, liver TAT activity was not related to serum tyrosine levels. TAT activity increased when an adenosine A2 agonist, 5'-N-ethylcarboxamide adenosine, was given. Since TAT activity is increased by cAMP, and ethanol increases cAMP production via an adenosine receptor-dependent mechanism, this increase in ethanol-induced TAT activity may occur via an adenosine receptor-dependent mechanism.
Effects of green tea catechins comprising EGCg, EGC, ECg, EC, GCg, GC, Cg, and C were determined on blood glucose tolerance and oxidative stress status in type 2 diabetic Goto-Kakizaki (GK) rats. GK rats fed the catechin-containing diet tended to maintain blood glucose and systolic blood pressure at lower levels in the latter stages of the feeding period of 76 d, compared to those not receiving dietary catechins (control group). The blood glucose tolerance test performed on days 48-49 showed that GK rats fed the catechins had lower blood glucose levels than GK rats not fed catechins during the 120 min after glucose loading. In catechin-fed rats, amounts of 8-OH dG and albumin excreted into the urine determined on days 71-72, and kidney ACE activity determined on day 76, were lower than those in control rats. From these results it is concluded that dietary catechins may be effective in delaying the progression of diabetes and the associated oxidative stress.
We examined the effects of different types of buckwheat sprouts on the plasma cholesterol concentration, fecal steroid excretion and hepatic mRNA expression related to cholesterol metabolism in rats. Rats were fed a cholesterol-free diet with 5 g of Kitawasesoba common buckwheat sprout powder (KS)/100 g, 5 g of Hokkai T no. 8 tartary buckwheat sprout powder (HS-8)/100 g or 5 g of Hokkai T no. 9 tartary buckwheat sprout powder (HS-9)/100 g of diet for 4 wk. Control rats were fed a diet with α-cornstarch instead of sprout powder for 4 wk. There were no significant differences in food intake, body weight, liver weight or cecal contents among the groups. Plasma total cholesterol concentrations in the HS-8 and HS-9 groups were significantly lower than in the control group, whereas there was no significant difference between the KS and control groups. Fecal bile acid excretion and cecal short-chain fatty acid concentrations in the KS, HS-8 and HS-9 groups were significantly greater than in the control group. Furthermore, fecal matter excretion in the KS, HS-8 and HS-9 groups tended to be increased compared to the control group, with that in the HS-8 group being significantly higher than in the control group. Hepatic cholesterol 7α-hydroxylase mRNA expression in the KS, HS-8 and HS-9 groups and hepatic HMG-CoA reductase mRNA expression in the HS-9 group were significantly higher than in the control group. The results suggest that tartary buckwheat sprout powder has a serum cholesterol-lowering function by enhancing fecal bile acid excretion through increased fecal matter excretion or the upregulation of hepatic cholesterol 7α-hydroxylase mRNA expression in rats.
The purpose of this study was to examine which component in the microbial protease-resistant fraction of Katsuobushi (KBR), smoke-dried bonito, is hypocholesterolemic in ovariectomized rats (OVX-rats). KBR contains two major components: oil and protease-resistant protein. Oil extracted from KBR (EX) was rich in palmitic, oleic and docosahexaenoic acids. OVX-rats were fed one of the following diets for 28 d: diets containing casein as the protein source (C or C+EX diet), a diet containing KBR as the protein source (KBR diet) or diets containing degreased KBR as the protein source (DF/KBR or DF/KBR+EX diet). The C and DF/KBR diets contained soybean oil as the oil source. In the C+EX, KBR and DF/KBR+EX diets, soybean oil was replaced by oil extracted from KBR (EX). Plasma total- and low density lipoprotein-cholesterol concentrations in the C+EX, KBR and DF/KBR+EX groups, but not in the DF/KBR group, were significantly lower than that in the C group. Fecal bile acid excretion was significantly greater in the C+EX, KBR, DF/KBR and DF/KBR+EX groups in comparison to the C group, whereas excretion in the KBR and DF/KBR+EX groups was significantly greater than in the C+EX and DF/KBR groups. Cholesterol 7α-hydroxylase activity was higher in the C+EX, KBR, DF/KBR and DF/KBR+EX groups than the C group. In OVX-rats fed C, C+EX or KBR for 28 d, bile acid flux into the small intestine increased in KBR and C+EX groups in comparison to the C group. The hypocholesterolemic effect of KBR in OVX-rats reflected in increased fecal bile acid excretion may be mediated by increased bile acid flux caused by EX and the binding of bile acids by protease-resistant proteins.
Fatty acids in milk are thought to play an important role in intestinal maturation and gene expression in the postnatal small intestine. In this study, we determined the jejunal mRNA levels, in rats, of peroxisome proliferator-activated receptor α (PPARα) and PPARδ which are nuclear receptors for fatty acids. We also measured expression of their target genes during the postnatal period, namely liver type fatty acid-binding protein (L-FABP) and cellular retinol-binding protein, type II (CRBPII). The mRNA levels of PPARα, L-FABP and CRBPII, but not PPARδ, gradually increased during the suckling period and then sharply declined to a low level at the end of the weaning period. Rat pups at 17 d of age, weaned to a high-fat diet, showed significantly greater mRNA levels of PPARα, L-FABP and CRBPII than those weaned to a low-fat diet. Oral administration of PPARα ligand, WY14,643 during four consecutive days of the weanling period caused a parallel increase in the mRNA levels of PPARα, L-FABP and CRBPII genes. Furthermore, caprylic acid and oleic acid, which are major components of fatty acids in milk, induced jejunal PPARα, L-FABP and CRBPII gene expression. Our results suggest that fatty acids in milk may play a pivotal role in maintaining an enhanced level of expression of L-FABP and CRBPII genes in the small intestine, presumably by acting as inducers of PPARα gene expression.
Epidemiological evidence regarding dental status and its relationship to diet and nutritional status has been limited. The present cross-sectional study examined the relationship between intake of vegetables, fruit, grains, antioxidants, and fiber and the prevalence of tooth loss. Study subjects were 1,002 pregnant Japanese women. Tooth loss was defined as the previous extraction of 1 or more teeth. Adjustment was made for age, gestation, parity, cigarette smoking, passive smoking at home and at work, family income, education, changes in diet in the previous 1 mo, season when data were collected, and body mass index. Of the 1,002 subjects, 256 women had lost 1 or more teeth. Compared with intake of vegetables other than green and yellow vegetables in the lowest quartile, consumption of the other vegetables in the highest quartile was independently associated with a decreased prevalence of tooth loss, showing a clear inverse dose-response relationship. There was a marginally significant inverse dose-response relationship between the intake of insoluble fiber and tooth loss. No association was observed between intake of green and yellow vegetables, soluble fiber, or antioxidant nutrients and tooth loss. These findings suggested that consumption of vegetables other than green and yellow vegetables and insoluble fiber may be related to a decreased prevalence of tooth loss among young Japanese women.
It has been demonstrated in a previous study that resting energy expenditure (REE) is associated with adiponectin levels in the blood. However, body composition was not taken into consideration in that study. The purpose of the present study was to again investigate the relationship between blood adipocytokines and REE, adjusted by body composition, in both young and elderly women. REE and blood adipocytokines were measured in 115 young (age: 22.3±2.1 y, BMI: 21.3±1.9 kg/m2) and 71 elderly (63.4±6.5 y, 22.9± 2.3 kg/m2) women. Dual energy X-ray absorptiometry was used to measure percent body fat. Fat mass and fat free mass (FFM) were calculated. REE (kcal/d and kcal/kg BW/d) was lower in elderly women than in young women, but no significant difference was observed in REE, expressed as kcal/kg FFM/d, between the two groups. Although elderly women had a higher percent body fat and higher serum leptin concentrations than young women, plasma adiponectin concentrations did not differ between young and elderly women. In elderly women, REE (kcal/d) was significantly and inversely correlated with plasma adiponectin concentration (r=−0.386, p<0.001), but REE expressed per kilogram of BW or FFM was not significantly correlated. Furthermore, no significant correlation was observed between REE (kcal/d) and concentrations of plasma adiponectin or serum leptin, after adjusting for potential confounders such as body composition and hormones, in either age group. These results suggest that adipocytokines do not influence REE in adult women.
Active Hexose Correlated Compound (AHCC) is an extract of Lentinula edodes of the basidiomycete family of fungi rich in alpha glucans. AHCC has been used for many years as a dietary supplement to enhance the immune system and in clinical trials as an adjunctive treatment in Hepatocellular cancer. This multiple dose, Phase I trial, using FDA guidelines, directly investigates the clinical safety and tolerability of AHCC in healthy subjects. Its safety has been based previously on anecdotal reports and its use in clinical practice. Twenty-six healthy male or female subjects between the ages of 18 and 61 were recruited from the community and gave their consent to participate in the trial. The subjects were given 9 g of AHCC (150 mL of the currently available liquid AHCC) PO daily for 14 d. Laboratory data was obtained at baseline and after 14 d of exposure to AHCC and adverse events were monitored by a non-directed review of systems questionnaire three times during the trial. At each visit the vital signs and adverse events were recorded. Two subjects (7%) dropped out because of nausea and intolerance of the liquid. Adverse effects of nausea, diarrhea, bloating, headache, fatigue, and foot cramps occurred in a total of 6 subjects (20%) but were mild and transient. There were no laboratory abnormalities. When used in high dose in healthy subjects, AHCC causes no significant abnormality in laboratory parameters. The adverse effects of 9 g of liquid AHCC per day, a higher dose than used in routine clinical applications, are minimal and the dose was tolerated by 85% of the subjects.
Cape aloe (Aloe ferox Miller) has been a herb well known for its cathartic properties and has also been used popularly as a health drink (juice, tea and tonic) in the United States and in Europe. Cape aloe extract also has been reported to possess several pharmacological effects, such as anti-inflammatory, anti-bacterial, anti-fungal and protective effect against liver injury. However, the investigations on an anti-tumor activity in cape aloe extract are very few and subsequent mechanisms have not been well elucidated. In this study, we examined the effect of the selective growth inhibitory activity of cape aloe extract and found that the cape aloe extract, especially the dichloromethane (CH2Cl2) extract, caused a dose-dependent growth inhibitory effect in Ehrlich ascites tumor cells (EATC), but not in mouse embryo fibroblast (NIH3T3) cells, which was used as a normal cell model. Furthermore, the CH2Cl2 extract caused an accumulation of cells in the G1 phase and a decrease of cells in the S and G2/M phase of the cell cycle and inhibited DNA synthesis in a dose-dependent manner. In addition, other results suggest that cell cycle arrest and inhibition of proliferation in EATC by the CH2Cl2 extract are associated with decreased retinoblastoma protein (Rb) phosphorylation.
The lipolysis induced by Satsuma mandarin orange (Citrus unshu Mark) was investigated using rat fat cells. Peel or segment wall extract from Satsuma mandarin orange induced the lipolysis in a concentration-dependent manner, whereas juice sac extract did not induce the lipolysis. High concentration of synephrine, which is an adrenergic amine, was detected in the peel or segment wall extract, whereas it was not detected in the juice sac extract. The segment wall extracts from Iyokan and orange had high lipolytic activity, whereas the extracts from grapefruit and lemon did not have lipolytic activity. The β-antagonist inhibited the lipolysis elicited by the segment wall extract from Satsuma mandarin orange, whereas α-antagonist did not inhibit the lipolysis induced by the segment wall. The lipolysis induced by the segment wall was considerably higher in the visceral fat cells when compared to the subcutaneous fat cells. These results suggest that the segment wall, an edible fraction, from Satsuma mandarin orange might be useful as a functional food, especially as a fat-reducing material.
Muscle mass is regulated by the synthesis and degradation of muscle protein, which in turn are affected by aging, several catabolic diseases, and malnutrition. Amino acids, particularly leucine, are known to stimulate muscle protein synthesis and suppress muscle protein degradation, although their long-term effects are unclear. The objective of our research was to elucidate whether long-term feeding of a protein-free or low-protein diet supplemented with leucine suppresses myofibrillar protein degradation. The rate of myofibrillar protein degradation was measured by the rate of release of 3-methylhistidine (MeHis) from isolated extensor digitorum longus (EDL) muscle. The weight of gastrocnemius muscle decreased in rats fed a protein-free diet for 7 d; however, a leucine-supplemented (1.5%) diet tended to suppress this decrease. The release of MeHis from EDL muscle was increased by the protein-free diet and decreased by the feeding of a diet supplemented with leucine to the level of a 20% casein diet. When rats were fed a 5% casein diet, the gastrocnemius muscle weight decreased and MeHis release from EDL muscle increased compared to those fed a 20% casein diet. However, feeding of a 5% casein diet supplemented with leucine (1.15%) reduced muscle weight loss and MeHis release. These results suggest that long-term feeding of leucine suppresses the rate of myofibrillar protein degradation and muscle weight loss in rats fed a protein-deficient diet.
Androgen receptor (AR) functions as a transcriptional factor for the development and progression of prostate cancer. Resveratrol is known to inhibit the function of AR and to repress AR expression at the transcriptional level. This study focuses on the effects of resveratrol on the AR function and the post-translational AR level. Resveratrol repressed the transcriptional activities of a mutant AR lacking the ligand-binding domain, a constitutive active form of AR, and wild-type AR in a concentration-dependent manner in human prostate cancer PC-3 cells, indicating that resveratrol does not inhibit the transcriptional activity of AR through binding to the ligand-binding domain of AR. Furthermore, the half-life of AR protein was approximately 4 h in resveratrol-treated AR-positive prostate cancer LNCaP cells, compared to approximately 13 h in control cells, as determined by cycloheximide chase. These results indicate that resveratrol down-regulates AR protein through a post-translational mechanism and suggest that the inhibitory effect of resveratrol on AR function is partly attributable to a decrease in the post-translational AR level.