Transport of Taurine by Normal Human Blood Platelets

Ahtee, Lisa; Boullin, D. J.; Paasonen, M. K.

doi:10.1111/j.1476-5381.1974.tb09707.x

Cited by 50 publications

(15 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…System ␤ activity has been demonstrated previously in adult platelets (1,16), adult leucocytes (34), fetal platelets (27), and a mixed population of cord blood cells composed mainly of leucocytes and platelets (50). Recently, TAUT mRNA expression has been confirmed in adult platelets (42).…”

mentioning

confidence: 89%

Taurine transporter in fetal T lymphocytes and platelets: differential expression and functional activity

Iruloh

D'Souza²,

Speake³

et al. 2007

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

Transplacental transfer of taurine, a ␤-amino acid essential for fetal and neonatal development, constitutes the primary source of taurine for the fetus. Placental transport of taurine is compromised in pregnancies complicated by intrauterine growth restriction, resulting in a reduced concentration of taurine in cord plasma. This could impact on fetal cellular metabolism as taurine represents the most abundant intracellular amino acid in many fetal cell types. In the present study, we have used pure isolates of fetal platelets and T lymphocytes from cord blood of placentas, from normal, term pregnancies, as fetal cell types to examine the cellular uptake mechanisms for taurine by the system ␤ transporter and have compared gene and protein expression for the taurine transporter protein (TAUT) in these two cell types. System ␤ activity in fetal platelets was 15-fold higher compared with fetal T lymphocytes (P Ͻ 0.005), mirroring greater TAUT mRNA expression in platelets than T lymphocytes (P Ͻ 0.005). Cell-specific differences in TAUT protein moieties were detected with a doublet of 75 and 80 kDa in fetal platelets compared with 114 and 120 kDa in fetal T lymphocytes, with relatively higher expression in platelets. We conclude that greater system ␤ activity in fetal platelets compared with T lymphocytes is the result of relatively greater TAUT mRNA and protein expression. This study represents the first characterization of amino acid transporters in fetal T lymphocytes. cord blood cells; amino acid; taurine transporter protein; system ␤ TAURINE (2-aminoethanesulfonic acid) is the most abundant free amino acid in several tissues, including the placenta and the cellular components of blood (9,21,38,41,46). It is a ␤-amino acid with the sulfonic acid group attached to the ␤-carbon atom and is not incorporated into proteins (14). The physiological functions of taurine are diverse, including bile and xenobiotic conjugation, regulation of neuronal excitability, membrane protection, antioxidation, detoxification, and osmoregulation (22,24,31). The nutritional requirements for taurine are met both by dietary sources and biosynthesis from cysteine and methionine (53). However, in the human fetus and the neonate, taurine is an essential amino acid, as biosynthetic capacity is almost negligible (51) due to the lack of cysteine sulfonic acid decarboxylase, which catalyses the rate-limiting step in taurine synthesis (4). Transplacental transfer of taurine from maternal blood therefore constitutes the primary source of fetal taurine.Taurine is transported across cell membranes, including those of the syncytiotrophoblast, the transporting epithelium of human placenta, by the system ␤-amino acid transport system which is specific for taurine and other ␤-amino acids such as ␤-alanine and hypotaurine (29,32,36). System ␤ is a highaffinity, low-capacity transport system that is Na ϩ -and Cl Ϫ -dependent (10) with a 2:1:1 Na ϩ :Cl Ϫ :taurine stoichiometry (39, 48). System ␤ activity has been demonstrated in many cell types and its ca...

show abstract

mentioning

confidence: 89%

Taurine transporter in fetal T lymphocytes and platelets: differential expression and functional activity

Iruloh

D'Souza²,

Speake³

et al. 2007

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

show abstract

“…The carrier is competitively inhibited by B-alanine and hypotaurine (8-9, 12, 14-16). In some tissue taurine is transported by a dual mechanism of active transport at lower concentrations and diffusion at higher concentrations ( 15,(17)(18)(19). The only human tissues in which taurine transport has been studied are platelets, lymphocytes, retina and, very recently, placental vesicles (14, 18-2 1).…”

mentioning

confidence: 99%

Taurine Transport in the in Vitro Perfused Human Placenta

et al. 1990

View full text Add to dashboard Cite

ABSTRACT. Taurine, required by the fetus for nutrition and neurological development, is inadequately synthesized by the fetus and substantial quantities of the amino acid are supplied by the mother. Maternal to fetal unidirectional taurine transport was studied in in vitro perfused human placentae from normal term deliveries. To determine whether the placenta can achieve and maintain a chemical gradient for taurine, recirculating equimolar maternal and fetal perfusions were performed. The ratio of fetallmaternal taurine concentration increased over 75 min and was maintained at 1.38 f 0.14 (SEM) through 2.25 h (n = 6).To determine the rate of taurine transport against a concentration gradient, flux was determined with maternal taurine constant at 50 pM whereas the fetal taurine concentration varied from 0 to 500 pM in a nonrecirculating system (n = 5). Despite increasing the chemical gradient tenfold, taurine was transported at a constant rate of 1.75 f 0.75 (SEM) nmol/min/g. Nonrecirculating perfusions were performed with B-alanine (n = 13) and hypotaurine

show abstract

“…Its formed elements can be models for components of ocular tis sues. Blood platelets possess a high affinity T uptake system, resembling the one found in retinal pigment epithelium [21]. It has been reported that T uptake is lower than normal in patients with RP [22]; the concentration of T and aspartate of platelets, calculated per number of platelets, was found significantly lower in RP patients than in controls [23].…”

Section: Discussionmentioning

confidence: 99%

Is Taurine a Marker for Retinitis pigmentosa ?

Benini

Marconcini²,

Wirth³

et al. 1988

Ophthalmologica

View full text Add to dashboard Cite

In view of contrary reports in the literature on anomalies of taurine concentration in the blood of retinitis pigmentosa patients, taurine clearance has been determined in 19 patients and 17 controls. No significant difference has been found between the average values of the two populations. The taurine content in cataractous crystalline lenses of retinitis pigmentosa patients has been found higher than the taurine content in lenses with senile cataract, but the same behaviour was also shown by five selected proteogenic amino acids. The results are discussed together with related literature data to conclude that taurine can be involved at least in some subtypes of retinitis pigmentosa, but cannot be considered as a marker for the disease.

show abstract

Transport of Taurine by Normal Human Blood Platelets

Cited by 50 publications

References 11 publications

Taurine transporter in fetal T lymphocytes and platelets: differential expression and functional activity

Taurine transporter in fetal T lymphocytes and platelets: differential expression and functional activity

Taurine Transport in the in Vitro Perfused Human Placenta

Is Taurine a Marker for Retinitis pigmentosa ?

Contact Info

Product

Resources

About