Transcellular transport of creatinine in renal tubular epithelial cell line LLC-PK1.

Background/aim: Creatinine is excreted into urine via tubular secretion in addition to glomerular filtration. In the present study, characteristics of the creatinine transport in renal epithelial cells were investigated.

Methods: The transcellular transport and accumulation of [14C]creatinine and [14C]tetraethylammonium (TEA) were assessed using LLC-PK1 cell monolayers cultured on porous membrane filters.

Involvement of specific transport system of renal basolateral membranes in distribution of nicotine in rats.

We measured the nicotine concentrations in tissues after a bolus i.v. administration of [(3)H]nicotine to rats to characterize the distribution profile of nicotine.

Creatinine transport by basolateral organic cation transporter hOCT2 in the human kidney.

Purpose: Creatinine is excreted into urine by tubular secretion in addition to glomerular filtration. The purpose of this study was to clarify molecular mechanisms underlying the tubular secretion of creatinine in the human kidney.

Methods: Transport of [14C]creatinine by human organic ion transporters (SLC22A) was assessed by HEK293 cells expressing hOCT1, hOCT2, hOCT2-A, hOAT1, and hOAT3.

[Molecular diversity of organic cation transporter (OCT) mediating renal excretion of drugs].

Tubular absorption and urinary secretion are important physiological functions for the maintenance of body fluid homeostasis and detoxification of drugs and xenobiotics. The proximal tubular epithelial cells play a principal role in limiting or preventing the toxicity of administered drugs by actively secreting organic cations from the circulation into the urine. Rat (r) OCT2 was identified as a second member of the organic cation transporter (OCT) family and is predominantly expressed in the kidney.

cDNA cloning, functional characterization, and tissue distribution of an alternatively spliced variant of organic cation transporter hOCT2 predominantly expressed in the human kidney.

A cDNA coding a novel organic cation transporter, hOCT2-A, was isolated from human kidney. The hOCT2-A cDNA is an alternatively spliced variant of hOCT2 with an insertion of 1169 bp. The open reading frame encodes a 483-amino acid protein that has 81% amino acid identity with hOCT2.

Gene expression levels and immunolocalization of organic ion transporters in the human kidney.

Renal excretion of organic anions and cations is mediated by the organic ion transporter family (SLC22A). In this study, the mRNA levels of the organic ion transporters were quantified by real-time PCR in normal parts of renal tissues from seven nephrectomized patients with renal cell carcinoma, and the distributions and localization of human (h)OAT1, hOAT3, and hOCT2 proteins were investigated by immunohistochemical analyses in the human kidney. The expression level of hOAT3 mRNA was the highest among the organic ion transporter family, followed by that of hOAT1 mRNA.