Influence of food on the gastric motor effect of the Kampo medicine rikkunshito in rat.

BACKGROUND: Rikkunshito, one of the Kampo medicines, is widely prescribed as a remedy for various upper gastrointestinal syndromes. The effect of rikkunshito is related to endogenous ghrelin and its active ingredient atractylodin enhances ghrelin receptor signaling. Kampo medicines are traditionally administered before or between meals; however, no definitive benefit of the timing of administration has been proven yet. To clarify the influence of food on the pharmacological action of rikkunshito, we investigated the gastric motor activity and pharmacokinetic profiles of atractylodin after the administration of rikkunshito in fasted and fed rats. METHODS: Phase III-like contractions in the gastric antrum after an injection of ghrelin were measured using a strain gauge force transducer. Rikkunshito was administered to rats during fasting or after a nutrient test meal. Ghrelin was injected 30 minutes later and gastric motility was evaluated. Furthermore, after rikkunshito administration, the pharmacokinetic profiles of atractylodin in the plasma and brain of fasted and free-fed rats were assessed. KEY RESULTS: Rikkunshito administration potentiated ghrelin-induced phase III-like contractions under fasting conditions. This effect was attenuated in animals fed a test meal. Atractylodin was detected pharmacokinetically in the plasma and brain after rikkunshito administration in rats, and free-fed rats exhibited a decreased maximum concentration of plasma atractylodin and a delayed time to reach the maximum concentration. CONCLUSIONS & INFERENCES: We show that the pharmacological action of rikkunshito is influenced by food in rats. The efficacy of rikkunshito may be associated with decreased absorption of its active ingredient atractylodin when food is in the stomach.

Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1.

Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP-CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan.

Ghrelin enhancer, rikkunshito, improves postprandial gastric motor dysfunction in an experimental stress model.

BACKGROUND: Functional dyspepsia (FD) is one of the most common disorders of gastrointestinal (GI) diseases. However, no curable treatment is available for FD because the detailed mechanism of GI dysfunction in stressed conditions remains unclear. We aimed to clarify the association between endogenous acylated ghrelin signaling and gastric motor dysfunction and explore the possibility of a drug with ghrelin signal-enhancing action for FD treatment. METHODS: Solid gastric emptying (GE) and plasma acylated ghrelin levels were evaluated in an urocortin1 (UCN1) -induced stress model. To clarify the role of acylated ghrelin on GI dysfunction in the model, exogenous acylated ghrelin, an endogenous ghrelin enhancer, rikkunshito, or an α2 -adrenergic receptor (AR) antagonist was administered. Postprandial motor function was investigated using a strain gauge force transducer in a free-moving condition. KEY RESULTS: Exogenous acylated ghrelin supplementation restored UCN1-induced delayed GE. Alpha2 -AR antagonist and rikkunshito inhibited the reduction in plasma acylated ghrelin and GE in the stress model. The action of rikkunshito on delayed GE was blocked by co-administration of the ghrelin receptor antagonist. UCN1 decreased the amplitude of contraction in the antrum while increasing it in the duodenum. The motility index of the antrum but not the duodenum was significantly reduced by UCN1 treatment, which was improved by acylated ghrelin or rikkunshito. CONCLUSIONS & INFERENCES: The UCN1-induced gastric motility dysfunction was mediated by abnormal acylated ghrelin dynamics. Supplementation of exogenous acylated ghrelin or enhancement of endogenous acylated ghrelin secretion by rikkunshito may be effective in treating functional GI disorders.

Rikkunshito induces gastric relaxation via the ß-adrenergic pathway in Suncus murinus.

BACKGROUND: Rikkunshito (RKT) is a gastroprotective herbal medicine. In this study, we investigated the role of RKT in the relaxation of the gastric body (fundus and corpus) and antrum. METHODS: We used Suncus murinus, a unique small model animal with similar gastrointestinal motility to humans and dogs. RKT was added at 0.1, 1.0, and 5.0 mg/mL to induce relaxation in vitro; the outcome measure was the intensity of relaxation. The number of spontaneous antral contractions in the absence or the presence of RKT was also counted. KEY RESULTS: Rikkunshito induced the relaxation of the gastric body and antrum and decreased the number of spontaneous antral contractions in a dose-dependent manner. The responses to RKT (1.0 mg/mL) were not affected by pretreatment with atropine, N-nitro-l-arginine methyl ester, ritanserin, or ondansetron. On the other hand, timolol almost completely reversed the relaxation induced by RKT (1.0 mg/mL) on the gastric body and antrum and the occurrence of the spontaneous antral contractions. Both butoxamine, a ß(2) -adrenoreceptor antagonist, and L 748337, a ß(3) -adrenoreceptor antagonist, but not CGP 20712, a ß(1) -adrenoreceptor antagonist, significantly reversed the RKT-induced (1.0 mg/mL) gastric relaxation. CONCLUSIONS & INFERENCES: These results indicate that RKT stimulates and modulates gastric relaxation through ß(2) - and ß(3) -adrenergic, but not ß(1) -adrenergic, pathways in S. murinus.

Insulin secretion and interleukin-1ß dependent mechanisms in human diabetes remission after metabolic surgery.

To compare endocrine, metabolic, and inflammatory changes induced by gastric bypass (GB) and sleeve gastrectomy (SG) in patients with type 2 diabetes mellitus (T2DM), and to investigate the mechanisms of success after metabolic surgery. Sixteen GB and 16 SG patients were followed up before and at 1 year after surgery. The 75-g oral glucose tolerance test (OGTT) was performed before and after surgery. Glucose homeostasis, serum interleukin-1ß, plasma gut hormones and adipokines, and the United Kingdom Prospective Diabetes Study (UKPDS) ten-year cardiovascular risks were evaluated. The diabetes remission rate was significantly higher in GB than SG. Changes in the area under the curve (AUC) for glucose were greater in those with complete and partial remission after GB and remitters after SG than non-remitters after SG, whereas changes in AUC for C-peptide were higher in complete and partial remitters after GB than non-remitters after SG. Insulinogenic index was enhanced and serum interleukin-1ß was reduced in complete remitters after GB and remitters after SG. Logistic regression analysis confirmed that insulinogenic index and interleukin-1ß, not insulin resistance, were the factors determining the success of diabetes remission after metabolic surgeries. GB and SG significantly reduced the ten-year risk of coronary heart disease and fatal coronary heart disease in T2DM patients after surgery, while GB had the additional benefit of reduced stroke risk. Human diabetes remission after metabolic surgery is through insulin secretion and interleukin-1ß dependent mechanisms. GB is superior to SG in cardiocerebral risk reduction in Asian non-morbidly obese, not well-controlled T2DM patients.

Potentiation of ghrelin signaling attenuates cancer anorexia-cachexia and prolongs survival.

Cancer anorexia-cachexia syndrome is characterized by decreased food intake, weight loss, muscle tissue wasting and psychological distress, and this syndrome is a major source of increased morbidity and mortality in cancer patients. This study aimed to clarify the gut-brain peptides involved in the pathogenesis of the syndrome and determine effective treatment for cancer anorexia-cachexia. We show that both ghrelin insufficiency and resistance were observed in tumor-bearing rats. Corticotropin-releasing factor (CRF) decreased the plasma level of acyl ghrelin, and its receptor antagonist, α-helical CRF, increased food intake of these rats. The serotonin 2c receptor (5-HT2cR) antagonist SB242084 decreased hypothalamic CRF level and improved anorexia, gastrointestinal (GI) dysmotility and body weight loss. The ghrelin receptor antagonist (D-Lys3)-GHRP-6 worsened anorexia and hastened death in tumor-bearing rats. Ghrelin attenuated anorexia-cachexia in the short term, but failed to prolong survival, as did SB242084 administration. In addition, the herbal medicine rikkunshito improved anorexia, GI dysmotility, muscle wasting, and anxiety-related behavior and prolonged survival in animals and patients with cancer. The appetite-stimulating effect of rikkunshito was blocked by (D-Lys3)-GHRP-6. Active components of rikkunshito, hesperidin and atractylodin, potentiated ghrelin secretion and receptor signaling, respectively, and atractylodin prolonged survival in tumor-bearing rats. Our study demonstrates that the integrated mechanism underlying cancer anorexia-cachexia involves lowered ghrelin signaling due to excessive hypothalamic interactions of 5-HT with CRF through the 5-HT2cR. Potentiation of ghrelin receptor signaling may be an attractive treatment for anorexia, muscle wasting and prolong survival in patients with cancer anorexia-cachexia.

Glycogen depletion in intrafusal fibres in rats during short-duration high-intensity treadmill running.

AIM: The recruitment patterns of the intrafusal and extrafusal fibres in the soleus (SOL) and extensor digitorum longus (EDL) muscles of rats were investigated during brief-intensity exercise by assaying their glycogen content histochemically. METHODS: Six adult male rats were assigned to each of four groups that ran up a 6 degrees incline on a motor-driven treadmill, at 40 m min(-1) for either 0.5, 1, 2, or 4 min. Six adult male rats in the control group did not run. Extrafusal and intrafusal fibres were classified by myosin ATPase staining. Optical densities for glycogen content were evaluated in serial periodic acid Schiff (PAS) stained-sections from the B and C regions of intrafusal fibres. RESULTS: The glycogen content of type IIA fibres in the SOL and EDL muscles decreased significantly in the early phase of exercise whereas the glycogen content of type I fibres in these muscles decreased later than that of type IIA fibres. The glycogen content of bag2 fibres decreased after 1 min of exercise in the SOL muscle and after 2 min of exercise in the EDL muscle. On the other hand, the glycogen content of bag1 and chain fibres decreased significantly after 2 min in the SOL muscle but not in the EDL muscle. CONCLUSION: The results suggest that during brief-intensity exercise, as the glycogen content of type IIA fibres is reduced earlier than that of type I fibres, bag2 fibres are most important early in this type of exercise.

The alpha-ketoisocaproate catabolism in human and rat livers.

Catabolism of alpha-ketoisocaproate in liver is mediated by cytosolic alpha-ketoisocaproate dioxygenase (KICD) and mitochondrial branched-chain alpha-keto acid dehydrogenase complex (BCKDC). The latter is believed to be involved in the main pathway of the KIC catabolism. In the present study, we measured the activities of KICD and BCKDC in human and rat livers. The KICD activity in human liver was 0.9 mU/g tissue, which was 14.2% of the total activity of BCKDC, and that in rat liver was 4.2 mU/g tissue, which was only 1.0% of the total activity, suggesting that KICD in human liver plays a relatively important role in the alpha-ketoisocaproate catabolism. The KICD activity in human liver was significantly increased by cirrhosis. In rat liver, the enzyme activity was markedly increased by physical training and streptozotocin-induced diabetes, but not by feeding of a diet rich in branched-chain amino acids, although BCKDC activity was increased by feeding of the diet.

Suppression of glycogen consumption during acute exercise by dietary branched-chain amino acids in rats.

The effects of a diet supplemented with branched-chain amino acids (BCAA; 4.8% or 6.2%) on BCAA catabolism and glycogen metabolism in rats were examined. Rats were fed a BCAA diet or control diet for 4 wk and part of the rats were subjected to exercise training during the experimental period. Feeding the BCAA diet increased serum BCAA concentrations and activity of the hepatic branched-chain alpha-keto acid dehydrogenase complex, the rate-limiting enzyme in the catabolism of BCAA, suggesting that dietary BCAA promotes BCAA catabolism. Although the serum glucose concentration and glycogen contents in the liver and gastrocnemius muscle of rested rats were not significantly affected by feeding of the BCAA diet, those in rats exhausted by acute exercise were 2-4-fold higher in rats fed the BCAA diet than in rats fed the control diet. The activity of pyruvate dehydrogenase complex in the liver and gastrocnemius muscle after acute exercise showed reverse trends; the complex activities (especially in liver) tended to be less in the BCAA diet group than in the control diet group. These results suggest that dietary BCAA spares glycogen stores in liver and skeletal muscle during exercise and that the decrease in pyruvate dehydrogenase complex activity in these tissues by dietary BCAA is involved in the mechanisms.

Exercise training prevents maturation-induced decreases in insulin receptor substrate-1 and phosphatidylinositol 3-kinase in rat skeletal muscle.

We have previously reported that exercise training prevents a maturation-induced decrease in insulin sensitivity and suggested that an improvement of insulin sensitivity by exercise training was attributable, in part, to an increase in insulin-sensitive GLUT-4 on the skeletal muscle plasma membrane. In this study, we examined the effects of maturation and exercise training on the gene expression and protein content of the components of post-insulin receptor signal transduction in rat skeletal muscle. Rats aged 3 weeks were sedentary or trained by voluntary running through 4 or 27 weeks of age, and then the rats in both the sedentary and trained groups were killed and the gastrocnemius muscle was immediately removed for analysis of mRNA and protein content. The concentration of mRNA and protein for insulin receptor substrate-1 (IRS-1) in sedentary rats significantly decreased with maturation (49% and 63%, respectively, at age 27 weeks v age 4 weeks), but in trained rats they did not decrease with maturation. Although the level of phosphatidylinositol 3-kinase (PI 3-kinase) mRNA in sedentary rats was not altered with maturation, PI 3-kinase protein in sedentary rats significantly decreased with maturation (73% at 27 weeks v 4 weeks). However, PI 3-kinase protein in trained rats did not decrease with maturation. These results suggest that the prevention of maturation-induced decreases in the protein content of IRS-1 and PI 3-kinase is involved in the mechanisms responsible for the improvement of insulin sensitivity by exercise training, and exercise training may affect transcriptional regulation of the IRS-1 gene and posttranscriptional regulation of PI 3-kinase expression.

The abundance of mRNAs for pyruvate dehydrogenase kinase isoenzymes in brain regions of young and aged rats.

The abundance of mRNAs for pyruvate dehydrogenase kinase (PDK) isoenzymes in four brain regions of young (10 wk) and aged (50 wk) rats was investigated by reverse transcription-polymerase chain reaction (RT-PCR). The mRNAs for PDK1, 2, and 4 were detected in all the regions examined. The level of PDK2 mRNA was the most abundant among the isoenzymes in all the brain regions when judged from the PCR cycles. The level of PDK1 mRNA was relatively high in cerebellum and cerebral cortex compared to medulla oblongata and hippocampus. Aging decreased the levels of mRNAs for PDK1 and 2 in cerebellum and increased the PDK2 mRNA in hippocampus and cerebral cortex. The level of PDK4 mRNA was not affected by aging. These results provide the first evidence suggesting that there is the regional difference in the abundance of mRNAs for PDK isoenzymes in rat brain and that the levels of mRNAs for the isoenzymes were affected by aging.

Insulin activation of pyruvate dehydrogenase complex is enhanced by exercise training.

We studied the effects of exercise training on the activity of the pyruvate dehydrogenase (PDH) complex in rat gastrocnemius muscle (experiment 1) and the response of the complex to glucose and insulin infusion (euglycemic clamp) in trained and sedentary rats (experiment 2). In experiment 1, half of the rats were randomly allocated as sedentary animals and the other half were trained by voluntary running exercise for 8 weeks. The total activity of the PDH complex was not affected by exercise training, and the activity state (proportion of the active form) of the PDH complex was decreased from 15.0%+/-2.4% to 7.5%+/-1.1% by exercise training. The activity of 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase ([3-HADH] an enzyme in beta-oxidation) was significantly higher in trained versus sedentary rats. In experiment 2, sedentary and trained rats were starved for 24 hours before performing the euglycemic clamp. Glucose and insulin infusion was performed by a euglycemic clamp (insulin infusion rate, 6 mU/kg/min) for 90 minutes. The PDH complex was inactivated to less than 1% in both sedentary and trained rats after 24 hours of starvation. The glucose infusion rate (GIR) during the euglycemic clamp was higher in trained versus sedentary rats. The euglycemic clamp resulted in activation of the PDH complex in both sedentary and trained rats, but the response of the PDH complex to the euglycemic clamp was significantly higher in trained rats (5.8%+/-0.5%) than in sedentary rats (2.9%+/-0.5%). These results suggest that exercise training promotes fatty acid oxidation in association with suppression of glucose oxidation in skeletal muscle under resting conditions, but increases the rate of carbohydrate oxidation when glucose flux into muscle cells is stimulated by insulin.

Intramembrane structure of the sensory axon terminals in bullfrog muscle spindles.

Much physiologic and morphologic research has been done into the sensory mechanism of the frog muscle spindle. However, no freeze-fracture study has described in detail the shape and intramembrane structure of the nonmyelinated sensory axon terminals of the frog muscle spindle. In this study, muscle spindles were isolated from the red part of bullfrog semitendinous muscles. Chemically fixed spindles were subjected to freeze fracturing. The sensory axon endings were reconstructed, and the size and density of intramembrane particles (IMPs) were measured along the sensory nerve endings. The axon terminals had four distinctive parts: parent trunks (>0.5 microm in diameter), primary branches (0.15-0.5 microm), terminal branches (<0.1 pm), and varicosities (0.02-0.5 microm). IMPs ranged from 5 nm to 21 nm in diameter and were present in the intramembrane space of the plasma membrane all throughout the nonmyelinated sensory nerve endings. Mean IMP sizes in the protoplasmic face (PF) and the external face (EF), respectively, were 8.1 nm and 8.4 nm in the parent trunks, 8.8 nm and 8.8 nm in the primary branches, 9.4 nm and 9.0 nm in the varicosities, and 8.7 nm and 8.7 nm in the terminal branches. Mean IMP size in the PF was smallest in the parent trunk and largest in the varicosity. Mean IMP densities (numbers of IMPs per microm2) in the PF and the EF, respectively, were 2,500 and 700 in the parent trunks, 2,200 and 500 in the primary branches, 1,700 and 400 in the varicosities, and 1,000 and 300 in the terminal branches. Density decreased with the tapering of the axon terminal, with IMPs distributed evenly in the PF and the EF. The characteristic intramembrane structure of sensory nerve endings is discussed.

Induction of nuclear respiratory factor-1 expression by an acute bout of exercise in rat muscle.

Nuclear respiratory factor 1 (NRF-1) is a regulatory factor of nuclear genes for respiratory subunits and for components of the mitochondrial transcription and replication machinery. This study investigated the effects of an acute bout of aerobic exercise on the postexercise expression of mRNA for NRF-1 and RNA moiety of endonuclease for mitochondrial RNA processing (MRP-RNA) in soleus muscle of 5 days-trained and untrained rats. In the trained group, rats were run on a motor-driven treadmill at a speed of 25 m/min for 90 min/day for 5 days. On the final day, rats were run by the same procedures and were sacrificed at various postexercise time points (0.5, 3, 6, and 24 h). The basal level of cytochrome oxidase activity was increased by the training, which was associated with the increase in the expression of mRNAs for subunit VIc and III of the enzyme. The NRF-1 mRNA expression was transiently increased by approximately 35% at the time point of 6 h after exercise, although the basal level of the expression was not altered by training. A similar transient increase (approximately 50%) in NRF-1 expression by the acute bout of exercise was also observed in untrained rats. In contrast to the NRF-1 expression, the basal level of MRP-RNA abundance was not altered by 5 days training and was not affected by the single exercise bout in either 5 days-trained or untrained rats. These results suggest that the postexercise increase in NRF-1 mRNA expression in rat skeletal muscle may be an early response to endurance exercise for an enhancement of the mitochondrial oxidative capacity.

Dietary maltitol decreases the incidence of 1,2-dimethylhydrazine-induced cecum and proximal colon tumors in rats.

Maltitol is fermented in the colon due to only partial hydrolysis in the small intestine. In the present study, we examined effects of dietary maltitol on dimethylhydrazine-induced intestinal tumor in rats. In experiment 1, rats were fed a fiber-free diet or diets supplemented with 1 or 5 g/100 g maltitol for 27 wk. Each group of rats was injected with dimethylhydrazine or vehicle alone for the first 14 wk of the experimental period. Maltitol supplementation at 1 g/100 g of the diet significantly reduced tumor incidence in the cecum and the 5% supplement reduced tumor incidence in both the cecum and proximal colon in dimethylhydrazine-treated rats. In experiment 2, we investigated the effect of the 1 g/100 g maltitol diet on the short chain fatty acid concentrations in cecal contents of placebo and dimethylhydrazine-treated rats. Intake of the 1 g/100 g maltitol diet doubled (P < 0.05) the concentration of butyrate but did not affect acetate or propionate in the cecal contents. These results suggest that dietary maltitol has a protective effect against dimethylhydrazine-induced tumors in rat cecum and proximal colon and that butyrate produced by bacterial fermentation of maltitol in the cecum may be involved in the protection.

[Effects of onpi-to (TJ-8117) and (-)epicatechin-3-O-gallate on the proliferating changes in glomeruli of 5/6 nephrectomized rats].

Onpi-to (TJ-8117) is a herbal medicine composed of five crude drugs (Rhei Rhizoma, Glycyrrhizae Radix, Ginseng Radix, Zingiberis Rhizoma and Aconiti Tuber). Our previous experiments have demonstrated that TJ-8117 suppressed the development of glomerulosclerosis and retarded the deterioration of renal function in 5/6 nephrectomised rats. In the present study, the effects of TJ-8117 and (-)Epicatechin-3-O-gallate (ECG), which is a component of Rhei Rhizoma, on glomerular cell proliferation, extracellular matrix accumulation and glomerular hypertrophy were investigated in 5/6 nephrectomized rats. Male Wistar rats (170-180 g) were subjected to 5/6 nephrectomy, and TJ-8117 (0.32%, 0.64%) or angiotensin-converting enzyme inhibitor, captopril (CAP 0.08%) was administered daily by mixing in normal chow and ECG (2 mg, 8 mg/100 ml) by drinking water from the day after 5/6 nephrectomy. Following 5/6 nephrectomy, glomerular cell poliferation was increased and reached a maximum at 1 week in the untreated control rats, but was suppressed significantly at 1 and 2 weeks after treatment with TJ-8117 and at only 1 week after treatment with CAP. Extracellular matrix accumulation was detected after 1 week and increased gradually until 4 weeks in the control rats, whereas it was significantly inhibited in both the TJ-8117- and CAP-treated rats. In addition, immunohistochemistry revealed that TJ-8117 significantly inhibited the increase of fibronectin, and tended to reduce type I and type IV collagen at 4 weeks. Furthermore, TJ-8117 suppressed glomerular hypertrophy at 4 weeks. Systolic blood pressure (SBP) and urinary protein excretion (UP) were higher in the control rats than sham-operated rats. TJ-8117 prevented this increase of SBP and UP at 1 week. ECG also suppressed glomerular cell proliferation and the increase of SBP and UP at 1 week after 5/6 nephrectomy. These findings suggest that ECG was one of active components of TJ-8117. These results suggest that TJ-8117 suppressed proliferating changes in glomeruli at an early stage in 5/6 nephrectomized rats, and inhibited the development of glomerulosclerosis.

Gender difference in regulation of branched-chain amino acid catabolism.

Regulation of the activity state of the hepatic branched-chain 2-oxo acid dehydrogenase (BCODH) complex during the light-dark cycle differs markedly in male and female rats. Female rats exhibit a profound diurnal rhythm in the activity state of the complex that is not observed in male rats. Regardless of gender, most of the complex was dephosphorylated and active in the middle of the dark period and early in the light period, and this form of the complex predominated in male rats at the end of the light period. In contrast, most of the complex in female rats became phosphorylated and inactive by the end of the light period. Gonadectomy prevented the diurnal rhythm in females but was without effect in males, indicating that female sex hormones are required for this gender difference in regulation of the BCODH complex. Changes in levels of branched-chain 2-oxo acids, known regulators of BCODH kinase, do not seem to be involved; rather, an increase in BCODH kinase activity occurring between morning and evening is responsible for inactivation of the BCODH complex in female rats. The increase in kinase activity is due to an increase in the amount of kinase protein associated with the BCODH complex. Thus a marked diurnal variation in the amount of BCODH kinase and therefore its activity results in large swings in the activity state of the liver BCODH complex in female rats. This study provides the first evidence for a gender-specific difference in the regulation of branched-chain amino acid catabolism.

[Protective effect of onpi-to (TJ-8117) on the expression of apoptosis in 5/6 nephrectomized rats].

The present study was designed to clarify the effects of TJ-8117 on apoptosis in the glomeruli of 5/6 nephrectomized rats. TJ-8117 (400 mg/kg/day), captopril (50 mg/kg/day) and nicardipine (50 mg/kg/day) were administered as drinking water from the 56th day after renal ablation, and continued throughout the experiment. All rats were sacrificed at 13 weeks and renal tissues were removed to quantify histopathological and apoptotic parameters in glomeruli. TJ-8117 inhibited proteinuria, matrix index and decrease in the number of total cells in glomeruli of nephrectomized rats. In addition, the increase in apoptotic body and DNA fragmentation was significantly inhibited in the TJ-8117-treated group. Captopril and nicardipine failed to inhibit both parameters. In 400 mg/kg of the TJ-8117 treated group, the number of Bcl -2 positive cells in the glomeruli was elevated compared with the 5/6 nephrectomized control group. In addition, the number of Bax positive cells in the TJ-8117 group was significantly suppressed in a dose-dependent manner. These results suggest that TJ-8117 may inhibit apoptosis in the late stage of this model by suppressing matrix accumulation and progression of glomerulosclerosis. The apoptosis-preventing effect may be mediated by decreased expression of Bax in the glomerular cells.

[Sairei-to may inhibit the synthesis of endothelin-1 in nephritic glomeruli].

In order to clarify the antinephritic mechanisms of Sairei-to (TJ-114), its effects on the synthesis and expression of endothelin-1 were evaluated in rats with anti-glomerular basement membrane (GBM) nephritis. TJ-114 was administered orally once daily from the 20th day after anti-GBM serum injection and was continued throughout the experiment. TJ-114 prevented proteinuria and histopathological changes in the glomeruli of nephritic rats. TJ-114 inhibited elevation of the endothelin-1 concentration in the supernatant from cultured glomeruli of nephritic rats and the endothelin-1 positive area in the glomeruli. TJ-114 inhibited the elevation of systolic blood pressure and the number of proliferating cell nuclear antigen (PCNA)-positive cells per glomeruli. We also found that the constitutive Kampo medicine in TJ-114, Gorei-san (TJ-17), inhibited the synthesis and expression of endothelin-1. In addition, the constitutive herbs TJ-17, alismatis rhizoma (Japanese name "Takusha") and hoelen (Japanese name "Bukuryou") inhibited the synthesis and expression of endothelin-1. These results indicate that the antinephritic actions of TJ-114 may be due partially to the inhibition of endothelin-1 synthesis in the glomeruli.

Enlargement glycogen store in rat liver and muscle by fructose-diet intake and exercise training.

This study investigated the effect of long-term intake of a fructose diet and exercise training on glycogen content in liver and skeletal muscle in female rats. Thirty-six rats (8 wk old) were divided into two dietary groups and were fed with a control (chow) diet or fructose diet (containing 20%) fructose) for 12 wk. During this period, one-half of the rats in each dietary group were trained by using a motor-driven treadmill (running speed of 25 m/min and duration of 90 min/day, 5 days/wk). The liver glycogen was increased by intake of a fructose diet and exercise training, and the content was in the following order: control-diet and sedentary rats < fructose-diet and sedentary rats < or = control-diet and trained rats < fructose-diet and trained rats in the ratio of 1:3.4:3.6:5.0. The glycogen content in gastrocnemius muscle showed the same trend as that in liver; the ratio was 1:1.3:1.3:1.6. These results indicate that both long-term intake of the fructose diet and exercise training synergistically increased glycogen in both tissues.