Tissue distribution kinetics of tetraethylammonium ion in the rat

Mintun, Mark A.; Himmelstein, Kenneth J.; Schroder, Richard L.; Gibaldi, Milo; Shen, Danny D.

doi:10.1007/bf01059385

Cited by 33 publications

(6 citation statements)

References 19 publications

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“…Interestingly, although there may be minor species differences, OCTN1 and OCTN2 are expressed in various tissues, while OCT1 and OCT2 are expressed in kidney, liver, and intestine. A previous study on the tissue distribution of TEA in rats demonstrated that TEA accumulated in several tissues, including heart, gut, lung, and skin as well as liver and kidney in rats . Since TEA is hydrophilic and does not readily cross the cell membrane without the participation of a specific transporter, these tissues presumably contain a TEA transporter.…”

Section: Discussionmentioning

confidence: 98%

Involvement of OCTN1 (SLC22A4) in pH-Dependent Transport of Organic Cations

et al. 2003

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OCTN1 (SLC22A4) transports cationic compounds such as tetraethylammonium in a pH-sensitive and sodium-independent manner in cultured cells, and is expressed in wide variety of tissues, including kidney, muscle, placenta, heart, and others. This study focused on the clarification of its subcellular distribution in kidney and on its driving force to throw light on the pharmacological and physiological roles of OCTN1. Uptake of [14C]tetraethylammonium by membrane vesicles prepared from HEK293 cells stably transfected with human OCTN1 cDNA was osmolarity-sensitive, and the Km of tetraethylammonium was 1.28 mM at intravesicular and extravesicular pH values of 6.0 and 7.4, respectively. Tetraethylammonium uptake was pH-dependent, and overshoot uptake was observed in the presence of an outwardly directed proton gradient. A protonophore and membrane potential affected the overshoot uptake. Furthermore, preloading tetraethylammonium in the vesicles significantly increased the rate of uptake of [14C]tetraethylammonium. In mouse kidney, OCTN1 was expressed predominantly at the apical membrane of cortical proximal tubular epithelial cells. It was concluded that OCTN1 is involved in renal excretion of organic cations across the apical membrane in a pH-dependent, membrane potential-sensitive manner and is affected significantly by the organic cations on the trans side, showing counter transport activity.

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Section: Discussionmentioning

confidence: 98%

Involvement of OCTN1 (SLC22A4) in pH-Dependent Transport of Organic Cations

et al. 2003

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“…The present study allowed a more physiologically relevant approach (Mintun et al 1980) which was based on direct observation of concentrations in the various tissues. Tissues with proportional specific activities over the 24-432 h observation period were considered to have similar kinetic behaviour.…”

Section: Discussionmentioning

confidence: 99%

Monitoring vitamin E pools in sheep tissue and plasma after intravenous dosing of radiotocopherol

Karpinski

Hidiroglou

1990

Br J Nutr

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The fate of radiotocopherol was studied in plasma and tissues of sheep at various intervals after injection of single intravenous doses of 3H-labelled D-&-tocopherol. Plasma samples were taken at regular intervals after dosing and selected tissues were taken from all sheep after slaughter and assayed for radioactivity and D-&-tocopherol. Sheep were killed in groups of five at 24,72, 96, 272 and 432 h postdosing. Plasma profiles were characterized as a sum of three exponential terms. A principal component analysis of tissue concentrations was carried ont to identify tissues with parallel profiles of log (disintegrations/min per pg) over time. Five groups of tissues with distinct uptake and elimination processes were identified. The D-&-tocopherol in the liver and heart appeared to be consistent with the post-distributive kinetics of a highly perfused shallow compartment, while lung kinetics appeared to reflect a non-linear kinetic process. The third group, which included the spleen, neck brachiocephalicus muscle and pancreas, had depletion rates parallel to those of plasma for 24-272 h, but slower decreases than plasma over 272-432 h. Hip gluteus muscle and kidney comprised a fourth group, with depletion parallel to plasma rates for 24-96 h but progressively slower than plasma decreases over 96-272 h. Adrenal kinetics resembled the fourth group, but had a more rapid decrease in specific activities over 24-72 h.

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“…Creatinine, being cleared mainly by glomerular filtration, provides direct information only on the capacity for glomerular filtration but in many circumstances may correlate poorly with the other func tions o f the nephron, namely, tubular secretion and reab sorption. Because o f this limitation, several compounds have been investigated for their ability to measure the secretory capacity o f the kidney; these include p-aminohippuric acid [2], phenolsulphonephthalein [3] and tetraethylammonium [4], However, these substances are all ex ogenous and therefore need to be infused. In addition, for organic anions such as p-aminohippurate, other anions that can accumulate in uraemic blood may inhibit the renal tubular secretion o f the marker [5].…”

Section: Introductionmentioning

confidence: 99%

Estimation of Renal Tubular Secretion in Man, in Health and Disease, Using Endogenous N-1-Methylnicotinamide

Maiza

Waldek

Ballardie

et al. 1992

Nephron

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We have been investigating the possibility of using the renal clearance of endogenous N-1-methylnicotinamide (NMN) as a marker of renal tubular function. Sixty-three subjects (11 healthy volunteers and 52 patients with renal impairment) were used for this study. The subjects were divided into three groups according to their creatinine clearance: group 1, over 80 ml/min; group 2, between 30 and 80 ml/min, and group 3, less than 30 ml/min. The correlation between NMN and creatinine clearance was compared for each group. A good correlation (r = 0.84) was found for groups 1 and 3 (r = 0.76), whereas for group 2, a poor correlation was found (r = 0.43). For subjects with mild renal impairment (group 2), there was clear evidence of glomerulo-tubular imbalance manifest by a larger variability in NMN clearance than creatinine clearance and an essentially non-parallel decline in these two parameters for this group. When all subjects were grouped together, the relationship between the clearance of NMN and of creatinine was best described by a 3-term polynomial equation (r = 0.93). NMN clearance is a potentially useful non-invasive marker of renal tubular function in man and provides additional information to that provided by the measurement of creatinine clearance alone. This substance should be more fully evaluated as a potential diagnostic aid.

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Tissue distribution kinetics of tetraethylammonium ion in the rat

Cited by 33 publications

References 19 publications

Involvement of OCTN1 (SLC22A4) in pH-Dependent Transport of Organic Cations

Involvement of OCTN1 (SLC22A4) in pH-Dependent Transport of Organic Cations

Monitoring vitamin E pools in sheep tissue and plasma after intravenous dosing of radiotocopherol

Estimation of Renal Tubular Secretion in Man, in Health and Disease, Using Endogenous N-1-Methylnicotinamide

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