Characteristics of taurine transport in rat hepatocytes in primary culture

Ohkuma, Seitaro; Tamura, Jun’ichi; Kuriyama, Kinya; Mukainaka, Teruo

doi:10.1002/cbf.290020204

Cited by 12 publications

(8 citation statements)

References 27 publications

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“…We have reported previously that both fresh and cultured hepatocytes have the capacity to accumulate taurine and cholic acid mainly by saturable carrier-mediated transport systems (13,19,20,26). In contrast, this study demonstrated that glycine is not accumulated in these cells.…”

Section: Discussioncontrasting

confidence: 81%

“…We have previously reported that taurine is mainly accumulated by a carrier-mediated transport system both in fresh and cultured hepatocytes (13,19). In addition, it was confirmed in the preliminary study that labeled taurine added into the incubation medium was conjugated with cholic acid in both fresh and cultured hepatocytes, which was analyzed by thin layer chromatography (18).…”

Section: Discussionmentioning

confidence: 66%

“…It has been demonstrated that cysteine is converted to hypotaurine via cysteine sulfinic acid and/or cysteic acid and finally to taurine in fresh and cultured hepatocytes (22) in the metabolic pathway from cysteine to taurine, has been also considered to be transported by these cells because taurine uptakes in these cells are competitively inhibited by hypotaurine (13,19). Based on these findings, the effects of the addition of cysteine and hypotaurine on the formation of taurine-conjugated bile acids were also examined.…”

Section: Discussionmentioning

confidence: 99%

“…The net amounts of transported glycine by both fresh and cultured hepatocytes were calculated using [3H]inulin as described in previous reports (13,19 (Fig. 1).…”

mentioning

confidence: 99%

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Roles of Endogenous and Exogenous Taurine and Glycine in the Formation of Conjugated Bi e Acids: Analyses Using Freshly Isolated and Primary Cultured Rat Hepatocytes

Ohkuma

Tamura

Kuriyama

1984

Japanese Journal of Pharmacology

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Abstract-The regulatory roles of intracellular taurine and glycine, transported and biosynthesized in hepatocytes, on the formation of conjugated bile acids were studied using freshly isolated hepatocytes (fresh hepatocytes) and hepatocytes in primary culture (cultured hepatocytes).Transported taurine significantly increased the rate of taurocholic acid formation both in fresh hepatocytes and cultured hepatocytes.Similarly, the addition of cysteine and hypotaurine, which were metabolically converted to taurine in hepatocytes, facilitated the formation of taurocholic acid in these cells. On the other hand, exogenous glycine into the incubation medium had no effect on the formation of glycocholic acid both in fresh and cultured hepatocytes.In contrast, the addition of serine and threonine, which are metabolically converted to glycine in hepatocytes, significantly increased the formation of glycocholic acid in fresh hepatocytes, although little effect of the additions of serine and threonine on the formation of glycocholic acid was noted in the case of cultured hepatocytes. The present results indicate that the formation of taurine-conjugated bile acids in hepatocytes is maintained by both transported and intracellularly formed taurine in hepatocytes, while that of glycine-conjugated bile acids is regulated by glycine formed within hepatocytes, but not by transported glycine.

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Section: Discussioncontrasting

confidence: 81%

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

“…The net amounts of transported glycine by both fresh and cultured hepatocytes were calculated using [3H]inulin as described in previous reports (13,19 (Fig. 1).…”

mentioning

confidence: 99%

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Roles of Endogenous and Exogenous Taurine and Glycine in the Formation of Conjugated Bi e Acids: Analyses Using Freshly Isolated and Primary Cultured Rat Hepatocytes

Ohkuma

Tamura

Kuriyama

1984

Japanese Journal of Pharmacology

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“…53) These findings revealed a considerable discrepancy between sites for the synthesis and conjugation of taurine, and it was hypothesized that this could be explained by clarifying the taurine transport system in hepatocytes. Although earlier trials implied the involvement of TauT in Na + -and concentration-dependent taurine uptake by hepatocytes, 56,57) the lack of TauT gene resulted in only a 30% reduction in the taurine content of liver parenchymal cells during the marked depletion of taurine shown by nonparenchymal liver cells, 58) suggesting a minor role of TauT in taurine uptake by hepatocytes.…”

Section: Hepatic Taurine Uptake Mediated By Gat2mentioning

confidence: 99%

Impact of SLC6A Transporters in Physiological Taurine Transport at the Blood–Retinal Barrier and in the Liver

Kubo

Akanuma

Hosoya

2016

Biological & Pharmaceutical Bulletin

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Cumulative studies showed that taurine (2-aminoethanesulfonic acid) contributes to a variety of physiological events. Transport study suggested the cellular taurine transport in an Na -and Cl -dependent manner, and the several members of SLC6A family have been shown as taurine transporter. At the inner blood-retinal barrier (BRB), taurine transporter (TauT/SLC6A) is involved in the transport of taurine to the retina from the circulating blood. The involvement of TauT is also suggested in γ-aminobutyric acid (GABA) transport at the inner BRB, and its role is assumed in the elimination of GABA from the retinal interstitial fluid. In the retina, taurine is thought to be a major organic osmolyte, and its influx and efflux through TauT and volume-sensitive organic osmolyte and anion channel (VSOAC) in Müller cells regulate the osmolarity in the retinal microenvironment to maintain a healthy retina. In the liver, hepatocytes take up taurine via GABA transporter 2 (GAT2/SLC6A13, the orthologue of mouse GAT3) expressed at the sinusoidal membrane of periportal hepatocytes, contributing to the metabolism of bile acid. Site-directed mutagenesis study suggests amino acid residues that are crucial in the recognition of substrates by GATs and TauT. The evidence suggests the physiological impact of taurine transporters in tissues.

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Comparison of uptake kinetics in freshly isolated suspensions and short‐term primary cultures of rat hepatocytes

Kukongviriyapan

Stacey

1989

Journal Cellular Physiology

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The apparent kinetics of uptake of various model substrates were examined for hepatocytes in suspension and primary culture up to 72 h. The ability of hepatocytes to take up taurocholate and ouabain was decreased in culture. Vmax for uptake of both substrates diminished rapidly with increasing time in culture. An increase in Km was observed in cultures 6 h after plating, but there was no further change with prolongation of culture time. The decrease of uptake of taurocholate and ouabain during culture may be due to the reduction in the number of transport carriers plus a decrease of affinity of the carrier to substrates. The nonsaturable component of cadmium uptake was much reduced in cultured cells compared with the suspensions. The saturable process was lower in 6 h culture but increased to a level comparable with the fresh cells at longer culture time. No significant change was found in the Km between suspensions and cultures. Uptake of alpha-aminoisobutyric acid was greater in culture while that of 3-O-methyl-D-glucose was relatively stable but about one-half that found in cell suspension. Thus, uptake of two substrates, taurocholate and ouabain, is clearly compromised with increasing time in primary culture, while uptake of the other substrates does not reflect such a dramatic decrease. It is therefore apparent that the cell preparation of choice in uptake studies depends on the substrate and the nature of the experiments.

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Characteristics of taurine transport in rat hepatocytes in primary culture

Cited by 12 publications

References 27 publications

Roles of Endogenous and Exogenous Taurine and Glycine in the Formation of Conjugated Bi e Acids: Analyses Using Freshly Isolated and Primary Cultured Rat Hepatocytes

Roles of Endogenous and Exogenous Taurine and Glycine in the Formation of Conjugated Bi e Acids: Analyses Using Freshly Isolated and Primary Cultured Rat Hepatocytes

Impact of SLC6A Transporters in Physiological Taurine Transport at the Blood–Retinal Barrier and in the Liver

Comparison of uptake kinetics in freshly isolated suspensions and short‐term primary cultures of rat hepatocytes

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