• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.113-118
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• 2002

Alpha-lipoic acid is a known hypoglycemic agent that may be useful in the treatment of diabetes. The objective of this study was to investigate the fate of glucose in isolated muscles incubated with lipoic acid by determining its direct effects on specific metabolic and signaling pathways. Soleus muscles from healthy rats were incubated with lipoic acid in the absence or presence of insulin. Glucose transport, glycogen synthesis, glucose oxidation and lipid synthesis were determined and affects on major pathways associated with insulin signaling were evaluated. Glucose transport was not significantly altered by the addition of lipoic acid to the incubation medium. However, lipoic acid decreased glycogen synthesis in comparison to controls. Glucose oxidation was moderately increased while de-novo lipid synthesis from glucose was inhibited. Wortmannin repressed insulin stimulation of glucose incorporation into glycogen, an effect that was augmented by the combined treatment of wortmannin and lipoic acid. Basal and insulin-stimulated serine phosphorylation of Akt was not changed by the addition of lipoic acid to the incubation medium. These data show that in this in vitro model, lipoic acid did not significantly affect glucose uptake but dramatically modified pathways of glucose metabolism within muscle tissue.

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.748-753
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• 2001

This study is to investigate the effects of capsaicin with high-fat diet on tissue glycogen contents in exercise-trained rats. Forty male Sprague-Dawley rats were offered a high-fat diet for 2 wks in individual cages and were exercise-trained by a animal treadmill running throughout the experimental period. After 2 wks of the prefeeding with high-fat diet, the rats were divided into two group: high-fat diet group(CON)and high-fat diet + capsaicin(0.014%) group(CAP). The rats were killed by decapitation at 10 hr(rest), 1 hr and 2 hr after treadmill running(27m/min, 6$^{\circ}$). Body weight and epididymal adipose tissure weight were significantly lower in CAP than in CON, but soleus muscle weight was not different between the two groups. Glycogen contents in liver, soleus and gastrocnemius white muscles were significantly lower in CAP than in CON at rest, 1 hr and 2 hr (p<0.05). However, glycogen content in gastrocnemius red muscle was significantly higher in CAP compared with CON at 2 hr after the exercise(p<0.05). These results indicate that capsaicin intake with high-fat diet would decrease glycogen contents in liver and muscle, however, this effect on glycogen metabolism could be changed by muscle type.

• Journal of Nutrition and Health
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• v.37 no.1
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• pp.15-22
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• 2004

The purpose of this study was to investigate the effect of butanol (BuOH) fraction of Alisma canaliculatum (Ac) and/or selenium (Se) treatment on glycogen level, lipid metabolism and lipid peroxidation in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were assigned to one of the five groups: normal, STZ-control, and three experimental groups (Ac group, Ac-Se group, and Se group). Diabetes was experimentally induced by intravenous administration of 45 mg/kg of STZ in citrate buffer. The BuOH fraction of Ac (400 mg/kg bw) was orally administered for 3 weeks. The Se group were fed a AIN-93 recommended diet mixed with Na$_2$SeO$_3$ (2 mg/kg diet). The liver glycogen level of Ac and Ac-Se groups were significantly higher, when compared with the STZ-control groups. The muscle glycogen level was not significantly differ among all groups. The levels of liver triglyceride were higher in Ac-Se group than the STZ-control group. Pancreas protein levels were significantly increased in Ac-Se group than STZ-control group. The concentration of liver malondialdehyde (MDA) was significantly decreased in Ac and Se groups and decreased in Ac-Se group. Administration of BuOH fraction of Alisma canaliculatum and selenium supplementation increased the liver glycogen and triglyceride levels, and reduced peroxidative liver damage in STZ induced diabetic rats. These results suggest that treatment with a BuOH fraction of Alisma canaliculatum in combination with selenium has no synergistic antioxidative effect. Selenium supplementation may lead a decrease MDA of liver in diabetic rats.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.1-12
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• 2002

Ecophysiologically diapause represents a syndrome of physiological and biochemical characteristics, all of which ensure survival during a long period of dormancy. Since, silkworm enters diapause as embryo at the early embryonic stage, the duration of egg life depends on the duration of embryonic diapause. The nature of diapause in silkworm, Bombyx mori, is primarily determined by genetic characters and endocrinologicnl mechanisms, mediated by environmental factors such as temperature and photoperiod. Hibernating potency value besides nucleic acid and carbohydrate metabolism, production and utilization of sorbitol are also equally responsible for induction, initiation, determination, maintenance and termination of diapause. Embryonic diapause in Bombyx moir, induced by active secretion of sub-oesophageal ganglion is attributed to hormonal system and metabolic adjustment, which serves to bring about a new physiological state. Metabolic conversion of trehalose to glycogen at induction, glycogen to sorbitol at initiation and sorbitol to glycogen at termination of diapause is correlated and in each metabolic shift a key enzyme becomes active in response to hormonal and environmental stimulation. An attempt has been made in this review article to discuss briefly the nature of embryonic diapause, influence of various factors on diapause nature, hormonal mechanism of diapause besides biochemical composition of egg, nucleic acid and carbohydrate metabolism, production and utilization of sorbitol in relation to induction, determination, maintenance, initiation and termination of diapause in the silkworm, Bombyx mori.

• Journal of Life Science
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• v.6 no.3
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• pp.171-177
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• 1996

It was carried out to find the carbohydrate metabolism for the glycogen utilization and the effects of low temperature(1$\circ$C, 5$\circ$C)on embryonic development of the silkworm, Bombyx mori L. The content of sorbitol and glycerol in the chillihg eggs stored at 5$\circ$C or 1$\circ$C on 24 hours after oviposition showed the highest level on the 50th day. After that, the corresponding value in the eggs stored at 5$\circ$C were decreased, and the value in the eggs stored at 1$\circ$C maintained the similar level. The trehalose level was rapidly increased on 50$\sim$60th day or thereabouts, and then, it was accumulated. When the eggs stored at low temperature were tranaferred and developed the embryo at 25$\circ$C, sorbitol and glycerol were respectively changed to glycogen. Futhemore, the content of trehalose and glucose showed specific of patterns with each embryonic stage at low temperature. With the aforementioned results, the intemediary metabolism of carbohydrate was discussed with regard to embryonic development of non-diapause eggs of silkworms.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.172-183
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• 2017

Vitamin A and its metabolites modulate insulin resistance and regulate stearoyl-CoA desaturase 1 (SCD1), which are also known to affect insulin resistance. Here, we tested, whether vitamin A-mediated changes in insulin resistance markers are associated with SCD1 regulation or not. For this purpose, 30-week old male lean and glucose-intolerant obese rats of WNIN/GR-Ob strain were given either a stock or vitamin A-enriched diet, i.e. 2.6 mg or 129 mg vitamin A/kg diet, for 14 weeks. Compared to the stock diet, vitamin A-enriched diet feeding improved hyperglycemia and glucose-clearance rate in obese rats and no such changes were seen in lean rats receiving identical diets. These changes were corroborated with concomitant increase in circulatory insulin and glycogen levels of liver and muscle (whose insulin signaling pathway genes were up-regulated) in obese rats. Further, the observed increase in muscle glycogen content in these obese rats could be explained by increased levels of the active form of glycogen synthase, the key regulator of glycogen synthesis pathway, possibly inactivated through increased phosphorylation of its upstream inhibitor, glycogen synthase kinase. However, the unaltered hepatic SCD1 protein expression (despite decreased mRNA level) and increased muscle-SCD1 expression (both at gene and protein levels) suggest that vitamin A-mediated changes on glucose metabolism are not associated with SCD1 regulation. Chronic consumption of vitamin A-enriched diet improved hyperglycemia and glucose-intolerance, possibly, through the regulation of intracellular signaling and glycogen synthesis pathways of muscle and liver, but not associated with SCD1.

• The Korean Journal of Zoology
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• v.7 no.2
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• pp.25-36
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• 1964

The present paper deals with the comparative study on phylogenic difference in the patterns of energy metabolism of brain slices of several vertebrate species by measuring oxygen consumptionwith glucose-6-phosphate, glucose-1-phosphate, glyceraldehyde-3-phosphate or glutamate as respiratory substrate employing Warburg's manometric method, by determination of the utilization rate of glucose using glucose-1-C14 by analyzing patterns of free amino acid distribution , and by histochemical determination using glucose-1-C14 by analyzing patterns of free amino acid distribution acid distribution , and by histochemical determination of glycogen contents. 1. Glucose enhances the oxygen consumption of brain slices of animals belinging to reptile, aves and mammalia while it shows a tendency to decrease that of animals belonging to pisces and amphibia. 2. Glucose-6--phosphate increase oxygen consumption more than glucose in every species examined, while glucose-1-phosphate and glyceraldehyde-3-phosphate increase that of Rana nigromaculata only . In general m, it appears that phosphosugars are more effective as a respiratory substrate to those species which have less endogenous respiration than to those having larger endogenous respiration. 3. Similar patterns of free amino acid distribution and the relative amount are found among the species and in every species examined glutamic acid is detected in the larges amount . ${\gamma}$-Amino butyric acid, glycine, alanine and aspartic acid are found in every species. 4. Ophicephalus showed less oxygen consumption than endogenous respiration when glutamate was added to the medium. When sodium fluoride was added, the oxygen consumption was some what increased . Such phenomenon wasnot found in the frog. 5. The result of histochemcial analysis of the brain showed that glycogen was abundantly present in the fish , amphibia , and especially in the reptile and that no distinctive grains of glycogen were found in the bird and mammal . From these facts, it may be supposed that anaerobic glycolysis as energy source dominates in fish and amphibia and aerobic respiration through the oxidation of glucose dominates in bird and mamal , the reptile occupying transitional position between these two categories. The way of obtaining energy for brain activity by the oxidation of glucose supplied from the circulating blood is seemed to be first acquired by reptile and the function is completed both in aves and mammal.

• Journal of Nutrition and Health
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• v.35 no.8
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• pp.825-833
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• 2002

The effects of dietary supplementation of Eleutherococcus senticosus, taurine and carnitine on maximal endurance exercise performance along with other related parameters were evaluated in rats that underwent aerobic exercise training for 6 weeks. Thirty-two male rats (4 weeks old) were randomly divided into 4 groups, and fed experimental diets and/or aerobic exercise trained according to the protocol: SC (sedentary control group), EC (exercise-trained control group), EE (exercise-trained Eleutherococcus senticosus-supplemented group), and EETC (exercise-trained Eleutherococcus senticosus, taurine and carnitine-supplemented group). The food efficiency ratio of EC rats was significantly lower than the value for SC rats (p < 0.01). Exercise-trained control animals (92 $\pm$ 8.8 min) could run significantly longer until exhausted on the treadmill than sedentary control rats (11 $\pm$ 0.8 min) (p < 0.001). Animals fed an Eleutherococcus senticosus-supplemented diet, and an Eleuthherococcus sonticosus, taurine and carnitine- supplemented diet while undergoing aerobic exercise training for 6 weeks exhibited, respectively, 8 and 5 minutes longer running performance until exhausted than the rats fed the control diet. The gastrocnemius muscle glycogen concentration of the rats, measured at 48 hours post maximal exercise performance test, was 43% higher in EC rats than the value for SC rats (p < 0.05), but was not different among EC, EE, and EETC rats. The mitochondrial citrate synthase activity of the soleus muscle was significantly higher in EC rats compared to the value for SC rats (p < 0.01), and showed a tendency to increase, without statistical significance, in EE or EETC rats compared to the value for EC rats. These results indicate that aerobic exercise training for 6 weeks significantly improved maximal exercise performance, muscle glycogen content along with citrate synthase activity, which are important in the energy metabolism of muscle under aerobic exercise. Dietary supplementation of Eleutherococcus senticosus in rats while undergoing aerobic exercise training improved maximal endurance exercise performance without significantly affecting muscle glycogen content and enzyme activities involved in energy metabolism during exercise. Taurine and carnitine supplementation failed to show an additive effect on maximal endurance exercise performance when consumed along with Eleutherococcus senticosus.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 1997.06a
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• pp.51-72
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• 1997

Diapause hormone (DH) is a neuropeptide hormone which is secreted from the suboesophageal ganglion (SG) and is responsible for induction of embryonic diapause of the silkworm, Bombyx mori. DH is isolated from SGs and determined to be a 24 amino acid peptide amide. The cDNA encodes the polyprotein precursor from which DH, pheromone biosynthesis activating neuropeptide (PBAN) and three other neuropeptides are released and become matured. The C-terminal FXPRL-NH2 sequence of DH is essential but not sufficient for expression of full activity. Recently, we have isolated a unique hydrohobic peptide (VAP peptide) with a slight diapause egg induceing activity from organic solvent extracts of the male adult heads of the silkworm. The VAP peptide itself has no diapause inducing activity, but enhances DH activity through reducing ED50 value and the threshold concentration of DH. The DH-PBAN gene is composed of 6 exons interrupted by 5 introns and is expressed in 12 neurosecretory cells of the SG. The incubation of eggs at 25$^{\circ}C$, which induces embryonic diapause in the progeny, caused DH-PBAN mRNA content to increase at 5 different stages in the life cycle. By contrast, a 15$^{\circ}C$ incubation only induced expression of the gene at the late phrase adult stage. The temperature-controlled expression of DH-PBAN gene is closely correlated to the incidence of diapause, indicating that DH-PBAN gene expression is the initial event leading to diapause induction. DH acts to stimulate trehalase activity in developing ovary to bring about hyprglycogenism in mature eggs, a prerequisite metabolism for diapause initiation. Using in vivo and in vitro systems, DH is clearly shown to induce trehalase gene expression in developing ovaries. New protein synthesis is not needed for this process, but a Ca2+-dependent proteinkinase seems to be involved. Quite recently, we have sucessfully applied a new and potent trehalase inhibitor (Trehazoline) to reudce glycogen content in developing ovaries. The eggs deficient in glycogen were also able to enter diapause as the natural eggs do, so that we could provide the new egg system to reconsider the diapause associated metabolism other than the glycogen-sorbitol metabolic system.

• Journal of Nutrition and Health
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• v.40 no.3
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• pp.211-220
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• 2007

The purpose of this study was to investigate that the effect of dietary fatty acid composition on pro- and macro-glycogen utilization and resynthesis. The analyses were further extended for different muscle fibers (type I, type II, & type IIb) as well as tissues (i.e., liver & heart). Total one hundred sixty Sprague-Dawley rats were used, and rats were randomly allocated into four experimental groups: animals fed standard chow diet (n=40), animals fed saturated fatty acid diet (n=40), animals fed monounsaturated fatty acid (n=40), and animals fed polyunsaturated fatty acid (n=40). Animals in each groups were further divided into five subgroups: sacrificed at REST (n=8), sacrificed at immediately after 3 hr swim exercise (P-0HR, n=8), sacrificed at one hour after 3 hr swim exercise (P-1HR, n=8), sacrificed at four hour after 3 hr swim exercise (P-4HR, n=8), and sacrificed at twenty-four hour after 3 hr swim exercise (P-24HR, n=8). Soleus (type I), red gastrocnemius (type IIa), white gastrocnemius (type IIb), liver, and heart were dissected out at appropriated time point from all animals, and were used for analyses of pro- & macro-glycogen concentrations. After 8 weeks of dietary interventions, there was no significant difference in body mass in any of dietary conditions (p>.05). After 3 hr swim exercise, blood lactate level was higher compared to resting conditions in all groups, but it was returned to resting value after 1 hr rest (p<.05). Free fatty acid concentration was higher in all high fat fed groups(regardless of fatty acid composition) than CHOW consumed group. At rest, pro- & macro-glycogen concentration was not different from any of experimental groups (p>.05). Regardless of forms of glycogen, the highest level was observed in liver (p<.01), and most cases of supercompensation after 3hr exercise observed in this study were occurred in CHOW fed tissues. Except heart muscle, all tissues used in this study showed that pro- and macro-glycogen concentration was significantly decreased after 3 hr exercise. Based on these results, two conclusions were made: first, there is no different level of glycogen content in various tissues regardless of types of fatty acids consumed and second, the highest mobilization rate would be demonstrated from CHOW fed animals compare to animals that consumed any kinds of fatty acid diet if prolonged exercise is applied.