• Preventive Nutrition and Food Science
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• v.16 no.2
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• pp.104-109
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• 2011

Recently, we have demonstrated that green tea extract (GTE) decreases the intestinal absorption of benzo[a]pyrene (BAP), which is an extremely lipophilic food contaminant. The present study was conducted to examine if an enteral infusion of GTE would influence the biliary secretion of BAP and lipids in rats. Female rats were fed an AIN-93G diet with or without (control) GTE at 5 g/kg diet for 4 week. Following the 4-week dietary treatment, rats with bile duct cannula were infused continuously for 8 hr at 3.0 mL/hr via a duodenal catheter with a lipid emulsion containing $4.0\;{\mu}mol$ BAP labeled with $^{14}C$ ($^{14}C$-BAP), $20.7\;{\mu}mol$ cholesterol, $452\;{\mu}mol$ triolein, and $3.1\;{\mu}mol$ ${\alpha}$-tocopherol, and $396.0\;{\mu}mol$ Na-taurocholate with or without 76.1 mg GTE powder in PBS buffer (pH, 6.4). Bile was collected hourly via bile cannula for an 8 hr period. Our results showed that bile flow did not differ between groups. However, the biliary secretion of $^{14}C$-BAP was significantly enhanced by GTE infusion, compared with those infused with the lipid emulsion alone. However, GTE did not affect the biliary outputs of cholesterol, fat, phospholipid and ${\alpha}$-tocopherol. These findings indicate that GTE has a profound stimulatory effect on the biliary excretion of BAP in rats, without affecting other biliary lipids. The mechanism(s) by which GTE enhances the biliary secretion of BAP remains to be investigated.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.97-105
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• 1997

The regulatory role of cyclic nucleotides in the expression of neutrophil responses has been examined. fMLP-stimulated superoxide production in neutrophils was inhibited by dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP), histamine, adenosine + theophylline, cAMP elevating agents, and 8-bromoguanosine 3' ,5' -cyclic monophosphate (8-BrcGMP) and sodium nitroprusside, cGMP elevating agents. Staurosporine, a protein kinase C inhibitor, genistein, a protein tyrosine kinase inhibitor and chlorpromazine, a calmodulin inhibitor, inhibited superoxide production by fMLP, but they did not further affect the action of DBcAMP on the stimulatory action of fMLP. DBcAMP, histamine, adenosine+theophylline and genistein inhibited myeloperoxidease release evoked by fMLP, whereas BrcGMP, sodium nitroprusside and staurosporine did not affect it. The elevation of $[Ca^{2+}]_i$ evoked by fMLP was inhibited by genistein and chlorpromazine but was not affected by staurosporine. DBcAMP exerted little effect on the initial peak in $[Ca^{2+}]_i$ response to fMLP but effectively inhibited the sustained rise. On the other hand, BrcGMP significantly inhibited both phases. fMLP-induced $Mn^{2+}$ influx was inhibited by either DBcAMP or BrcGMP. These results suggest that fMLP-stimulated neutrophil responses may be regulated by cAMP more than cGMP. cAMP and cGMP appear not affect stimulated responses by direct protein kinase C activation. Their regulatory action on the stimulated neutrophil responses may be not influenced by other activation processes.

• The Korean Journal of Pharmacology
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• v.31 no.3
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• pp.333-344
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• 1995

The effects of adenosine and $N^6-cyclopentyladenosine$ (CPA) on superoxide production, myeloperoxidase release and $Ca^{2+}$ mobilization stimulated by fMLP in neutrophils were investigated. The effects were also observed on the stimulatory actions of C5a and PMA and the responses in lipopolysaccharide-primed neutrophils. In addition, the involvement of cAMP in the inhibitory action of adenosine was examined. The fMLP-stimulated neutrophil respiratory burst, degranulation and intracellular $Ca^{2+}$ mobilization may be regulated by activation of adenosine receptors. Adenosine may not affect the stimulated neutrophil responses due to activation of protein kinase C. fMLP-stimulated respiratory burst in lipopolysaccharide-primed neutrophils may be less sensitive to adenosine, compared with nonprimed cells. The inhibitory effect of theophylline in the presence of adenosine on neutrophil responses appears to be ascribed to accumulation of intracellular cAMP.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1156-1168
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• 2007

The somatotropic (GH-IGF-I) axis consists of many hormonal and nutritional factors that control GH release from the somatotrophs in the anterior pituitary. The GH-releasing substances are GHRH and GHS (GHRP or ghrelin), while the GH release-inhibiting substances are somatostatin (SRIF), insulin-like growth factor-I (IGF-I), leptin and glucocorticoids. However, there is evidence showing that nutrition is involved in the control of the somatotropic axis. In addition, weaning is a drastic event for neonates because their alimentary and endocrine circumstances are changed due to the switch, even if gradual, from a liquid milk diet to one composed of such solids as hay and grains. The biological role of ghrelin is one of the hormonal factors that have been focused on ever since ghrelin was discovered at the end of the last century. A 27-amino acid peptide that is mainly synthesized and released from the abomasum epithelium, ghrelin has not been fully evaluated in relation to the somatotropic axis of the ruminant. It has also proven difficult even to investigate the cellular mechanisms of ghrelin action, because this hormone exerts animal-species-dependent actions via a complex set of intracellular signaling pathways. This is also the case for the action of leptin. Another substance, IGF-I, shows a partial inhibitory action on GH secretion in the ruminant. The effect of nutrition is also different among animal species. This is evident by the fact that undernutrition suppresses the circulating GH levels in rodents, but increases it in ruminants and humans. Recently, weaning has been shown to change the postprandial GH responses in ruminants; milk feeding increases, but hay and concentrate feeding suppress, the postprandial circulating GH levels. Even if the postprandial GH level is increased, the ghrelin level is decreased by milk feeding. Macronutrients also possess stimulatory and inhibitory actions on GH secretion in vivo and in vitro. These findings indicate the complexity of the control mechanisms of the somatotropic axis. In the present review, we summarize recent findings on the factors controlling the axis of the ruminant.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.469-476
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• 2016

This study was undertaken to evaluate the immunomodulatory effect of dead nano-sized Lactobacillus plantarum (nLp) in RAW 264.7 cells and murine primary splenocytes. nLp is a dead, shrunken, processed form of L. plantarum nF1 isolated from kimchi (a traditional Korean fermented cabbage) and is less than 1 μm in size. It was found that nLp treatment stimulated nitric oxide (NO) production more in RAW 264.7 macrophages than pure live L. plantarum (pLp), and that the stimulatory properties were probably largely derived from its cell wall. In addition, nLp induced murine splenocyte proliferation more so than pLp; in particular, a high dose of nLp (1.0 × 10¹¹ CFU/ml) stimulated proliferation as much as lipopolysaccharide at 2 μg/ml. Moreover, according to our cytokine profile results in splenocytes, nLp treatment promoted Th1 (TNF-α, IL-12 p70) responses rather than Th2 (IL-4, IL-5) responses and also increased Th17 (IL-6, IL-17A) responses. Thus, nLp stimulated NO release in RAW 264.7 cells and induced splenocyte proliferation more so than pLp and stimulated Th1 and Th17 cytokine production. These findings suggested that dead nLp has potential use as a functional food ingredient to improve the immune response, and especially as a means of inducing Th1/Th17 immune responses.

• IMMUNE NETWORK
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• v.12 no.6
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• pp.296-300
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• 2012

Silica nanoparticles, which are applicable in many industrial fields, have been reported to induce cellular changes such as cytotoxicity in various cells and fibrosis in lungs. Because the immune system is the primary targeting organ reacting to internalized exogenous nanoparticles, we tried to figure out the immunostimulatory effect of silica nanoparticles in macrophages using differently sized silica nanoparticles. Using U937 cells we assessed cytotoxicity by CCK-8 assay, ROS generation by CM-$H_2DCFDA$, intracellular $Ca^{{+}{+}}$ levels by staining with Fluo4-AM and IL-8 production by ELISA. At non-toxic concentration, the intracellular $Ca^{{+}{+}}$ level has increased immediately after exposure to 15 nm particles, not to larger particles. ROS generation was detected significantly in response to 15 nm particles. However, all three different sizes of silica nanoparticles induced IL-8 production. 15 nm silica nanoparticles are more stimulatory than larger particles in cytotoxicity, intracellular $Ca^{{+}{+}}$ increase and ROS generation. But IL-8 production was induced to same levels with 50 or 100 nm particles. Therefore, IL-8 production induced by silica nanoparticles may be dependent on other mechanisms rather than intracellular $Ca^{{+}{+}}$ increase and ROS generation.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1172-1175
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• 2007

We observed that exogenously applied ethanol changed the activities of aldehyde oxidases (AO) in the primary roots of maize (Zea mays). The stimulatory effect of ethanol on the aldehyde oxidase activities was concentration dependent; the AO activities were slightly weaker with 0.2 - 0.4% ethanol and stronger with 0.8 - 1.0% ethanol than the level of control. The promotion of AO activities was not explained by the increased transcription of two AO genes in maize. In contrast, ethanol strongly increased the amount of AO proteins, indicating that ethanol enhanced AO activities by promoting the translation. Among three alcohols including ethanol, methanol and isopropanol, only ethanol promoted AO activities. These results suggested that enhancement of AO activities was specific to ethanol, whose level could be naturally increased when the plant roots drove fermentation to overcome low oxygen stresses.

• Food Science of Animal Resources
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• v.36 no.4
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• pp.558-565
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• 2016

The aim of this study was to investigate the influence of proteolytic pork hydrolysate (PPH) on yoghurt production by Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Fresh lean pork was cut into pieces and mixed with deionized water and dealt with protease, then the resulting PPH was added to milk to investigate the effects of PPH on yoghurt production. The fermentation time, the viable cell counts, the flavor, free amino acids compounds, and sensory evaluation of yoghurt were evaluated. These results showed that PPH significantly stimulated the growth and acidification of the both bacterial strains. When the content of PPH reached 5% (w/w), the increased acidifying rate occurred, which the fermentation time was one hour less than that of the control, a time saving of up to 20% compared with the control. The viable cell counts, the total free amino acids, and the scores of taste, flavor and overall acceptability in PPH-supplemented yoghurt were higher than the control. Furthermore, the contents of some characteristic flavor compounds including acids, alcohols, aldehydes, ketones and esters were richer than the control. We concluded that the constituents of PPH such as small peptide, vitamins, and minerals together to play the stimulatory roles and result in beneficial effect for the yoghurt starter cultures growth.

• Development and Reproduction
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• v.21 no.2
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• pp.131-138
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• 2017

This study was conducted to investigate stimulatory effect of epidermal growth factor (EGF) on nuclear maturation and the expression level of EGF-receptor (EGFR), GM-130 (a marker of Golgi apparatus), transport protein Sec61 subunit beta ($Sec61{\beta}$), and coatomer protein complex subunit gamma 2 (COPG2) in porcine oocytes. The cumulus-oocyte complexes were collected from follicle with 3-6 mm in diameter. They were incubated in medium with/without EGF for 22 h (IVM I) and subsequently incubated hormone-free medium with/without EGF for 22 h (IVM II). Nuclear maturation state was checked by aceto-orcein stain. Protein expression of EGFR, GM-130, $Sec61{\beta}$, and COPG2 were measured by immunofluorescence. In results, nuclear maturation of oocytes in EGF non-treated oocytes were significantly lower than EGF-treated groups at IVM I or IVM II stage (P<0.05), whereas maturational rate in EGF treatment groups at both of IVM stage was higher in among the all treatment groups (P<0.05). EGFR, GM-130, $Sec61{\beta}$ and COPG2 were expressed in the cytoplasm of oocytes. Especially, GM-130 and EGFR were strongly expressed, but $Sec61{\beta}$ and COPG2 were weakly expressed in cortical area of cytoplasm. The protein level of GM-130, $Sec61{\beta}$, and COPG2 were significantly higher in the EGF-treated groups (P<0.05). However EGFR was no difference between non EGF-treated groups and control. In conclusion, EGF plays an important role in the systems for oocyte maturation with endoplasmic reticulum and Golgi apparatus. In addition, the protein levels of $Sec61{\beta}$ and COPG2 could be changed by EGF in the porcine oocytes during maturation.

• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.166-170
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• 2006

In this study, we investigated whether schizandrin, schizandrin-A, gomisin-A and uridine affect mucin secretion from cultured airway epithelial cells and compared the potential activities of these agents with the inhibitory action on mucin secretion by poly-1-lysine (PLL) and the stimulatory action by adenosine triphosphate (ATP). Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled using $^3H-glucosamine$ for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on $^3H-mucin$ secretion. The results were as follows: schizandrin-A and uridine increased mucin secretion at the highest concentrations ($2{\times}10^{-4}\;-\;10^{-3}M$). We conclude that schizandrin-A and uridine can stimulate mucin secretion via direct effect on airway mucin-secreting cells and suggest that these agents be further investigated for the potential use as mucoregulators during the treatment of chronic airway diseases.