• Journal of Pharmaceutical Investigation
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• v.25 no.2
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• pp.137-143
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• 1995

The peptide transporter can be utilized for improving the bioavailability of compounds that are poorly absorbed. Characterization of the dipeptide uptake into the human intestinal epithelial cells, HT-29 was investigated. The uptake of tritiated glycylsarcosine $([^3H]-Gly-Sar,\;0.1\;{\mu}Ci/ml)$ was measured in confluent or subconfluent HT-29, Caco-2, and Cos-7 cells. Uptake medium was the Dulbecco's Modified Eagle's Media (DMEM) adjusted to pH 6.0. Both HT-29 and Caco-2 cells expressed the dipeptide transporter significantly (p<0.005) but Cos-7 did not. Certain portions of passive uptake were observed in all three cell lines. Uptake of Gly-Sar was largest at 7 days after plating HT-29 cells with significant inhibition with 25 mM cold Gly-Sar (p<0.05). but expression ratio of the dipeptide transporter was 0.7, suggesting lower expression. The effect of pH on Gly-Sar uptake was not significant in the range of pH 6 to 8. Gly-Sar uptake was also inhibited with 50 mM carnosine, 25 mM Gly-Sar, and 35 mM cephalexin significantly (p<0.05). From above results the dipeptide transporter was expressed well in HT-29 cells and was similar to that in the small intestine, suggesting that large amounts of mRNA of the transporter from the cells can be obtained.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.63-76
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• 1996

The aim of present study was to characterize phosphate uptake and to investigate the mechanism for the insulin and insulin-like growth factor(IGF) stimulation of phosphate uptake in primary cultured rabbit renal proximal tubule cells. Results were as follows : 1. The primary cultured proximal tubule cells had accumulated $6.68{\pm}0.70$ nmole phosphate/mg protein in the presence of 140 mM NaCl and $2.07{\pm}0.17$ nmole phosphate/mg protein in the presence of 140 mM KCl during a 60 minute uptake period. Raising the concentration of extracellular phosphate to 100 mM$(48.33{\pm}1.76\;pmole/mg\;protein/min)$ induced decrease in phosphate uptake compared with that in control cells maintained in 1 mM phosphate$(190.66{\pm}13.01\;pmole/mg\;protein/min)$. Optimal phosphate uptake was observed at pH 6.5 in the presence of 140 mM NaCl. Phosphate uptake at pH 7.2 and pH 7.9 decreased to $83.06{\pm}5.75%\;and\;74.61{\pm}3.29%$ of that of pH 6.5, respectively. 2. Phosphate uptake was inhibited by iodoacetic acid(IAA) or valinomycin treatment $(62.41{\pm}4.40%\;and\;12.80{\pm}1.64%\;of\;that\;of\;control,\;respectively)$. When IAA and valinomycin were added together, phosphate uptake was inhibited to $8.04{\pm}0.61%$ of that of control. Phosphate uptake by the primary proximal tubule cells was significantly reduced by ouabain treatment$(80.27{\pm}6.96%\;of\;that\;of\;control)$. Inhibition of protein and/or RNA synthesis by either cycloheximide or actinomycin D markedly attenuated phosphate uptake. 3. Extracellular CAMP and phorbol 12-myristate 13 acetate(PMA) decreased phosphate uptake in a dose-dependent manner in all experimental conditions. Treatment of cells with pertussis toxin or cholera toxin inhibited phosphate uptake. cAMP concentration between $10^{-6}\;M\;and\;10^{-4}\;M$ significantly inhibited phosphate uptake. Phosphate uptake was blocked to about 25% of that of control at 100 ng/ml PMA. 3-Isobutyl-1-methyl-xanthine(IBMX) inhibited phosphate uptake. However, in the presence of IBMX, the inhibitory effect of exogenous cAMP was not significantly potentiated. Forskolin decreased phosphate transport. Acetylsalicylic acid did not inhibit phosphate uptake. The 1,2-dioctanoyl-sn-glycorol(DAG) and 1-oleoyl-2-acetyl-sn- glycerol(OAG) showed a inhibitory effect. However, staurosporine had no effect on phosphate uptake. When PMA and staurosporine were treated together, inhibition of phosphate uptake was not observed. In conclusion, phosphate uptake is stimulated by high sodium and low phosphate and pH 6.5 in the culture medium. Membrane potential and intracellular energy levels are also an important factor fer phosphate transport. Insulin and IGF-I stimulate phosphate uptake through a mechanisms that involve do novo protein and/or RNA synthesis and decrease of intracellular cAMP level. Also protein kinase C(PKC) is may play a regulatory role in transducing the insulin and IGF-I signal for phosphate transport in primary cultured proximal tubule cells.

• Korean Journal of Biological Psychiatry
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• v.1 no.1
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• pp.88-97
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• 1994

Many evidences are compatible with the correlation between the inhibition of [$^3H$] imipramine([$^3H$]IMI) and [$^3H$]paroxetine([$^3H$]PAT) binding to the 5-hydroxytryptamine(5-HT) transporter complex and the 5-HT uptake of 5-HT neurons and platelets, and most antidepressants have been shown to inhibit the [$^3H$]IMI and [$^3H$]PAT binding and the neuronal 5-HT uptake. However, several paradoxical research findings led to doubt about the pharmacological significance of the [$^3H$]IMI and [$^3H$]PAT binding sites. This study was carried to clarify the correlation between the [$^3H$]IMI and [$^3H$]PAT binding parameters and the tissue 5-HT content or/and [$^3H$]5-HT uptake in the rabbit platelet, which contains 40 times ad much 5-HT as that of human platelet and shows the 10 fold higher $B_{max}$ of the 5-HT transporter binding to a 5-HT uptake inhibitor. The rabbits were treated for 28 days with amitriptyline(4mg/kg/day : AP), fluoxetine(0.5mg/kg/day : FO), and sertraline(0.5mg/kg/day : SA) via an Alzet osmotic pump implanted for constant infusion. The [$^3H$]IMI binding $B_{max}$ and $K_d$ of the rabbit platelets were $6.4{\pm}1.2$pmol/mg protein and $10.9{\pm}2.1$nM and those in the [$^3H$]PAT binding were $8.6{\pm}1.1$pmol/mg protein and $1.6{\pm}0.3$nM, respectively. AP slightly increased $B_{max}$ of [$^3H$]IMI binding and both [$^3H$]IMI binding and [$^3H$]PAT binding $K_d$, and i contrast, it slightly decreased $B_{max}$ of [$^3H$]PAT binding. FO Slightly increased $K_d$ of both and [$^3H$]IMI and [$^3H$]PAT binding and slightly decreased $B_{max}$ of [$^3H$]IMI and [$^3H$]PAT binding. SA produced the significant increase of [$^3H$]PAT binding $B_{max}$ and the slight increase of both [$^3H$]IMI and [$^3H$]PAT binding $K_d$ and in contrast, it slightly decreased $B_{max}$ and of [$^3H$]IMI binding. And, the $V_{max}$ and $K_m$ of platelet [$^3H$]5-HT uptake were $24.2{\pm}2.4$pmol/$10^8$ platelets/min and $3.3{\pm}0.3$nM, respectively. The $V_{max}$ was little affected by AP, FO, or SA, but the [$^3H$]5-HT uptake $K_m$ value was moderately increased by FO. However, the platelet 5-HT content was moderately decreased by all of the 5-HT uptake inhibitors used in this study. These results seem to be consistent with the allosterical and competitive interaction of 5-HT uptake inhibiting antidepressants with each other as well as 5-HT in the 5-HT transporter binding, and provide no support for the view that the potencies of 5-HT uptake inhibitors to inhibit the [$^3H$]IMI or [$^3H$]PAT binding with 5-HT transporter complex correlate with their antidepressant potencies.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.221-224
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• 2002

Biomass of non-viable and dried brown marine algae Ecklonia radiata Turn. was used to examine Its cadmium uptake capability. Twelve different pretreatments on the algal biomass were prepared. Among these pretreatments, the algal biomass, which treated with 0.1 M NaOH and kept in water. bath (100$\^{C}$, 18 h) followed by washing with distilled water and squeezing, showed the highest amount of cadmium uptake as 1634 $\pm$ 195 mg/g dry biomass at pH 4.0 and 50$\^{C}$. Adsorption temperatures and pH levels played some Important role In cadmium uptake. However, cadmium uptake decreased dramatically at a lower pH than 4.0. Freundlich adsorption isotherm showed potent cadmium uptake capacity of the non-viable biomass. Pretreatments on the non-viable algal biomass shown in this study nay enhance the Eadmium removal in the industrial wastewater.

• Biomolecules & Therapeutics
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• v.16 no.3
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• pp.219-225
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• 2008

Taurine is the most abundant amino acid in many tissues and is found to be enhancing the bone tissue formation or inhibits the bone loss. Although it is reported that taurine reduces the alveolar bone loss through inhibiting the bone resorption, its functions of taurine and expression of taurine transporter (TauT) in bone have not been identified yet. The purpose of this study is to clarify the uptake mechanism of taurine in osteoblast using mouse osteoblast cell lines. In this study, mouse stromal ST2 cells and mouse osteoblast-like MC3T3-E1 cells as osteoblast cell lines were used. The activity of taurine uptake was assessed by measuring the uptake of [$^3H$]taurine in the presence or absence of inhibitors. TauT mRNA was detected in ST2 and MC3T3-E1 cells. [$^3H$]Taurine uptake by these cells was dependent on the presence of extracellular calcium ion. The [$^3H$]taurine uptake in ST2 cells treated with 4 mM calcium was increased by 1.7-fold of the control which was a significant change. In contrast, in $Ca^{++}$-free condition and L-type calcium channel blockers (CCBs), taurine transport to osteocyte was significantly inhibited. In oxidative stress conditions, [$^3H$]taurine uptake was decreased by TNF-$\alpha$ and $H_2O_2$. Under the hyperosmotic conditions, taurine uptake was increased, but inhibited by CCBs in hyperosmotic condition. These results suggest that, in mouse osteoblast cell lines, taurine uptake by TauT was increased by the presence of extracellular calcium, whereas decreased by CCBs and oxidative stresses, such as TNF-$\alpha$ and $H_2O_2$.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.1-5
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• 2008

Salt accumulation in soils of greenhouse due to the massive application of nitrogen fertilizers causes salt stress on the various crops, a serious problem in domestic agriculture. Since the majority of the salinity is nitrate, the excess nitrate should be removed; therefore, a bacterial strain having high capacity of nitrate uptake and identified as Enterobacter amnigenus GG0461 was isolated from the soils of greenhouse. Optimum conditions for the bacterial growth and nitrate uptake were investigated. GG0461 was able to grow without nitrate; however, nitrate facilitated the growth. The rate of nitrate uptake increased at alkaline pH and both growth and nitrate uptake were maximal at pH 8-9. When the initial pH of culture medium was increased to pH 8 or 9, it was decreased to neutral upon bacterial growth and nitrate uptake. These results imply that the major factor mediating bacterial nitrate uptake is a nitrate/proton antiporter. The fact was supported by the effect of nitrate addition in the absence of nitrate, since the addition of nitrate greatly increased the nitrate uptake and rapidly decreased pH of media.

• Biomolecules & Therapeutics
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• v.10 no.2
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• pp.99-103
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• 2002

Taurine has a neuroprotective action from oxidative stress in neural cell. In the present study, we studied taurine transport under basal and stressed conditions in conditionally immortalized rat brain capillary endothelial cell line (TR-BBB13) in vitro. The uptake of[$^3{H}$]taurine in the TR-BBB13 was increased by time-dependently and dependent on both Na$^{+}$ and Cl/ sup -/. Furthermore, $\beta$-alanine strongly inhibited the uptake of [TEX>$^3{H}$]taurine in the TR-BBB13. To study the effcts of oxidative stress on taurine transport, we used diethyl maleate (DEM) and lipopolysccharide (LPS). Diethyl maleate (DEM, $300\Mu\textrm{M}$) significantly reduced uptake of [TEX>$^3{H}$]taurine by time-dependently until 8 hr exposure in TR-BBB 13. But, the [TEX>$^3{H}$]taurine uptake was not changed by lipopolysccharide (LPS, 10 ng/ml) in TR-BBB13.3.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.31-40
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• 1993

It is essential to clone the peptide transporter in order to obtain better understanding of its molecular structure, regulation, and substrate specificity. Characteristics of an endogenous peptide transporter in oocytes were studied along with expression of an exogenous proton/peptide cotransporter from rabbit intestine. And further efforts toward cloning the transporter were performed. The presence of an endogenous peptide transporter was detected in Xenopus laevis oocytes by measuring the uptake of $0.25\;{\mu}M\;(10\;{\mu}Ci/ml)\;[^3H]-glycylsarcosine$ (Gly-Sar) at pH 5.5 with or without inhibitors. Uptake of Gly-Sar in oocytes was significantly inhibited by 25 mM Ala-Ala, Gly-Gly, and Gly-Sar (p<0.05), but not by 2.5 mM of Glu-Glu, Ala-Ala, Gly-Gly, Gly-Sar and 25 mM glycine and sarcosine. This result suggests that a selective transporter is involved in the endogenous uptake of dipeptides. Collagenase treatment of oocytes used to strip oocytes from ovarian follicles did not affect the Gly-Sar uptake. Changing pH from 5.5 to 7.5 did not affect the Gly-Sar uptake significantly, suggesting no dependence of the endogenous transporter on a transmembrane proton gradient. An exogenous $H^+/peptide$ cotransporter was expressed after microinjection of polyadenylated messenger ribonucleic acid $[poly\;(A)^+-mRNA]$ obtained from rabbit small intestine. The Gly-Sar uptake in mRNA-injected oocytes was 9 times higher than that in water-injected oocytes. Thus, frog oocytes can be utilized for expression cloning of the genes encoding intestinal $H^+/peptide$ cotransporters. Using the technique size fractionation of mRNA was sucessfully obtained.

• Journal of Pharmaceutical Investigation
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• v.36 no.4
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• pp.283-286
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• 2006

The present study aimed to investigate the interaction of nucleoside analogs with human organic anion transporter 1 and 3(hOAT1 and hOAT3) that play a primary role in the tubular uptake of endogenous and exogenous organic anions in the kidney. The interactions of ddC, ara-C, ara-A and ara-U with hOAT1 and hOAT3 were examined using MDCK cells stably overexpressing hOAT1 or hOAT3. Among the tested drugs, ddC showed the highest affinity to hOAT1 with $IC_{50}$ values of 5.2 mM, while ara-A, ara-C and ara-U weakly inhibited the cellular uptake of $[^3H]-PAH$ in MDCK-hOAT1 cells at 1 mM. In contrast, all the tested drugs did not have any inhibition effect on the cellular uptake of $[^3H]-estrone$ sulfate in MDCK-hOAT3 cells over the drug concentration of 0.01-2 mM, implying that they might not interact with hOAT3. Taken all together, the present study suggests that hOAT1 could weakly interact with nucleoside analogues such as ddC, ara-C, ara-A and ara-U but the interaction with hOAT3 during the urinary excretion of these nucleoside analogues may be negligible in the kidney.

• Fashion & Textile Research Journal
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• v.7 no.3
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• pp.321-326
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• 2005

The purpose of this study was to investigate the effect of body fat on energy metabolic response and subjective sensations under the hot environment. Fifteen female university students volunteered as subjects. We organized subjects into three groups: low body fat group(group L : less than 20% of body fat), medium body fat group(group M : 20%~30% of body fat) and high body fat group(group H: more than 30% of body fat). The experiment was conducted with $32^{\circ}C$, 60%RH. The subjects repeated 'Exercise' and 'Rest' period. The results of this study are as follows ; The oxygen uptake value of AM is higher than PM. The value of group H is the highest in three fat groups. But it showed group L is the highest in oxygen uptake per weight. %body fat is the lower, oxygen uptake is the higher. In Calorie, group L has higher value in AM in than in PM. In M group and group H, a value of PM is higher than AM. In group H, difference of AM and PM is the highest. From a view point of three groups, a value of group H is the highest. This support that calorie increases as oxygen uptake increase. The heart rate values of group L and group H are the higher in AM than in PM. This support that heart rate was relation to oxygen uptake. In all three groups, the value of blood pressure is higher in AM than in PM. Subjective sensations of temperature sensation, thermal comfort, and wetness sensation are higher in Am than in Pm. This explains that subject sensations are similar to experimental data, such as oxygen uptake, heart rate, blood pressure. In oxygen uptake, heart rate and blood pressure, general tend to showed higher AM than PM. This showed that heart rate, oxygen uptake increase in AM, as blood pressure increase, too. From a view point of %body fat, group H is higher than the others in oxygen uptake, heart rate and blood pressure.