• The Korean Journal of Physiology
• /
• v.30 no.2
• /
• pp.249-256
• /
• 1996

The effect of probenecid on the transport of tetraethylammonium (TEA) was studied in renal cortical slices and isolated membrane vesicles to investigate the interaction of organic anion with the organic cation transport system in proximal tubule. Probenecid reversibly inhibited TEA uptake by renal cortical slices in a dose-dependent manner over the concentration range of 1 and 5 mM. The efflux of TEA was not affected by the presence of 3 mM probenecid. Kinetic analysis indicated that probenecid decreased Vmax without significant change in Km. Probenecid inhibited significantly tissue oxygen consumption at concentrations of 3 and 5 mM. However, probenecid did not significantly reduce TEA uptake in brush border and basolateral membrane vesicles prepared from renal cortex even at a concentration as high as 10 mM. These results indicate that probenecid reduces TEA uptake in cortical slices by inhibiting tissue metabolism rather than by an interaction with the organic ration transporter.

• The Journal of Internal Korean Medicine
• /
• v.18 no.1
• /
• pp.147-155
• /
• 1997

This study was undertaken to determine whether Salviae-radix (SVR) exraction exerts benefical effect against oxidant-induced inhibition of tetraethylammonium (TEA) uptake which is actively secreted by renal proximal tubules. TEA uptake increased as function of incubation time to 60 min. When renal cortical slices were exposed to 50 mM $H_2O_2$, TEA uptake was significantly inhibited. The inhibition was significantly protected by addition of 0.5% SVR extraction. The benefical effect of SVR was dose-dependent over the concentration range of 0.1-1%; $H_2O_2$ (50 mM)-induced inhibition of TEA uptake was completely protected by 0.5-1% SVR extraction. $H_2O_2$ increased LDH release which was accompanied by an increase in lipid peroxidation in renal cortical slices. These changes were prevented by 0.5% SVR. These results suggest that SVR exerts benefical effect against oxidant-induced impairment of membrane transport function, this effect may be due to by an antioxidant action.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.24 no.1
• /
• pp.34-42
• /
• 2000

The colorante from black tea infusion were applied to cotton fabric. Dyeing properties were investigated in terms of dye uptakes at various dyeing conditions and the effect of mordants on color change and colorfastness. Cotton showed low affinity to black tea colorants. Effects of mordants on dye uptake was not significant except Sn. Irrespective of mordant type, color of cotton dyed with black tea colorants was brownish and colorfastness was generally good. In order to improve dye uptake, cotton was cationized by treating with Cationon UK(tertiary ammonium salt) and chitosan. Dye uptake of cotton was remarkably increased by cationizing. Cationon UK was more effective than chitosan.

• The Korean Journal of Physiology and Pharmacology
• /
• v.6 no.1
• /
• pp.21-26
• /
• 2002

Effects of cadmium (Cd) intoxication on renal endosomal accumulation of organic cations $(OC^+)$ were studied in rats using $^{14}C-tetraethylammnium$ (TEA) as a substrate. Cd intoxication was induced by s.c. injections of 2 mg Cd/kg/day for $2{\sim}3$ weeks. Renal cortical endosomes were isolated and the endosomal acidification (acridine orange fluorescence change) and TEA uptake (Millipore filtration technique) were assessed. The TEA uptake was an uphill transport mediated by $H^+/OC^+$ antiporter driven by the pH gradient established by $H^+-ATPase.$ In endosomes of Cd-intoxicated rats, the ATP-dependent TEA uptake was markedly attenuated due to inhibition of endosomal acidification as well as $H^+/TEA$ antiport. In kinetic analysis of $H^+/TEA$ antiport, Vmax was reduced and Km was increased in the Cd group. Inhibition of $H^+/TEA$ antiport was also observed in normal endosomes directly exposed to free Cd (but not Cd-metallothionein complex, CdMt) in vitro. These data suggest that during chronic Cd exposure, free Cd ions liberated by lysosomal degradation of CdMt in proximal tubule cells may impair the endosomal accumulation of $OC^+$ by directly inhibiting the $H^+/OC^+$ antiporter activity and indirectly by reducing the intravesicular acidification, the driving force for $H^+/OC^+$ exchange.

• Journal of Food Hygiene and Safety
• /
• v.11 no.2
• /
• pp.83-87
• /
• 1996

The objective of this study is to investigate the direct effects of green tea catechins(GTC) on vascular smooth muscle tension and 45Ca2+ Uptake in rat aorta. The methods used in this study are isometric tension measurements using physiograph, Lanthanum method for 45Ca2+(2 uCi/ml) uptake measurement in rat aorta. GTC modified tension induced by 40 mM KCl or 1 uM norepinephrine in rat aorta. Low concentrations of GTC(<0.5mg/ml) increased tension by 40 mM KCl or 1 uM norepinephrine, individually. However, high conecentration of GTC(>0.5 mg/ml) inhibiited tension by 40 mM KCl or 1 uM norepinephrine, individually. GTC increased 45Ca uptake induced by 40 mM KCl in a dose-dependent manner. From these results, GTC has the dual actions in vascular smooth muscle in vitro. Low concentrations of GTC augments tension by K or norepinephrine. However, high concentrations of GTC inhibits tension by K or norepinephrine GTC may have Ca2+ channel activation, action, which may result in unphysiological vasodilation by Ca2+ overload in vascular smooth muscle.

• The Korean Journal of Physiology
• /
• v.24 no.2
• /
• pp.345-352
• /
• 1990

To determine the role of sulfhydryl group in transport of organic ions across the basolateral membrane of renal proximal tubules, effect of p-chloromercuribenzoic acid (PCMB) on the transport of tetraethylammonium (TEA) and p-aminohippurate (PAH) was studied in rabbit renal cortical slices. PCMB caused irreversible inhibition of TEA and PAH uptake in a dose-dependent manner, with $I_{50}$ value (concentration for 50% inhibition) of $30\;{\mu}M$ for TEA and $75\;{\mu}M$ for PAH. Kinetic analysis of TEA and PAH uptakes showed that PCMB decreased Vmax $(62.35\;vs.\;28.32\;n\;mole/g{\cdot}min\;fur\;TEA:\;385.24\;vs.\;170.36\;n\;mole/g{\cdot}min\;for\;PAH)$ without changing Km. The inhibitory action of PCMB on TEA and PAH uptakes was independent of pH of the pretreatment medium. The inhibitory effect of PCMB on the uptake of TEA or PAH was prevented by dithiothreitol, but not by the substrate. PCMB inhibited Na-K-ATPase activity in a dose-dependent manner with $I_{50}$ value of $50\;{\mu}M$, which is similar to those for TEA and PAH uptake. These results suggest that PCMB inhibits the transport of organic cations and anions in the renal basolateral membrane by directly affecting the SH-group in the transporter molecules or secondly by altering the Na-K-ATPase activity.

• Food Science and Biotechnology
• /
• v.16 no.1
• /
• pp.167-170
• /
• 2007

(-)-Epigallocatechin-3-gallate (EGCG), a mai or tea catechin has been shown to have many interesting biological activities. In the present study, we studied the effects of green tea catechins, EGCG metabolites, and black tea theaflavins on accumulation of EGCG in HT-29 human colon cells. Intracellular levels of [$^3H$]-EGCG were not changed significantly in the presence of other tea catechins including (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate. EGCG methyl metabolites and EGCG 4"-glucuronide did not affect cellular levels of [$^3H$]-EGCG. Black tea theaflavins and theasinensin A (TsA), an EGCG oxidative dimer, however, significantly decreased cellular accumulation of EGCG in HT-29 cells by 31-56%. This decrease was more pronounced when cells were incubated in the presence of theaflavin-3',3"-digallate (TFdiG) or TsA. When EGCG was added separately from TFdiG or TsA, the accumulation of EGCG in HT-29 cells was also significantly decreased regardless of when TFdiG or TsA was added during the uptake study (p<0.01). The results suggest that theaflavins and TsA may interrupt EGCG absorption through the gastrointestinal epithelium.

• The Korean Journal of Physiology
• /
• v.25 no.2
• /
• pp.171-177
• /
• 1991

This study was carried out to determine effect of acute renal ischemia on transport function of organic cation, tetraethylammonium (TEA), in rabbit kidney proximal tubule. Clamping of the renal artery for 30 and 60 min produced a polyuria which was accompanied by an increase in $Na^+$ excretion. The capacity of kidney cortical slices to accumulate TEA was increased after 30 and 60 min of ischemia. When blood flow was restored for 30 min after 30 and 60 min of ischemia, the augmented TEA uptake was recovered to the control values. Oxygen consumption of cortical slices was stimulated after 30 min of ischemia, whereas it was not altered by 60 min of ischemia. A 90-min ischemia produced a significant inhibition of TEA uptake and tissue oxygen consumption. These results suggest that the basolateral transport system for organic cation persists after ischemic periods of 60 min despite evidence that tubular reabsorptive mechanism of $Na^+$ and water is markedly impaired. This may indicate that the active secretory systems of proximal tubule are more resistant to ischemic injury than the reabsorptive systems.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.4
• /
• pp.510-516
• /
• 1999

Dyeing properties of cotton fabrics with green tea colorants were studied by investigating the effects of dyeing conditions such as colorants concentration. pH dyeing temperature and time on dye uptakes effects of mordats on dye uptakes and color change and effects of cationizing agent on dye uptakes. And various colorfastnesses of dyed fabrics were evaluated for practical use. Green tea colorants showed low affinity to cotton and produced yellowish red color. Freundlich adsorption isotherm was obtained thus it is considered that hydrogen bondings are formed between colorants and cotton. Dye uptake was maximum at pH 5 and decreased as pH increased. Mordants especially Cu and Sn were effective for increasing dye uptake. Dye uptakes were improved remarkably by cationizing. Cationized cotton showed Langumuir adsorption isotherm indicating that ionic bondings were formed between colorants and cationized cotton. While mordanting did not affect lightfastness cationizing affected adversely. Colorfastness of cationized sample was generally inferior to that of mordanted samples.

• Journal of Acupuncture Research
• /
• v.18 no.4
• /
• pp.143-151
• /
• 2001

Objective : This study was undertaken to determine whether Scutellaria balicalensis Georgi (SbG) extract exerts the protective effect against oxidant-induced alterations in organic cation transport in the renal proximal tubule. Methods : Organic cation transport was estimated by examining alterations in tetraethylammon - ium(TEA) uptake in rabbit renal cortical slices. The slices were treated with 0.2 mM tBHP for 60 min at $37^{\circ}C$. tBHP caused an inhibition in TEA uptake by renal cortical slices. Such an effect was accompanied by depressed Na+-K+-ATPase activity and ATP depletion. tBHP also induced a significant increase in LDH release. Results : SbG prevented tBHP-induced inhibition of TEA uptake in a dose-dependent manner at the concentration ranges of 0.05-0.1%. tBHP-induced inhibition of Na+-K+-ATPase activity and ATP depletion were significantly prevented by 0.05% SbG. tBHP-induced LDH release also was blocked by SbG. tBHP caused a significant increase in lipid peroxidation and its effect was prevented by SbG. Conclusion : These results suggest that SbG prevents oxidant-induced alterations in organic cation transport in rabbit renal cortical slices. Such protective effects of SbG may be attributed to inhibition of peroxidation of membrane lipid.