title: OCTN2-mediated transport of carnitine in isolated Sertoli cells.
abstract: Carnitine is extensively accumulated in epididymis. Carnitine is also accumulated in testis at higher concentration than in the plasma and is used in spite of the presence of the blood-testis barrier. In this study, we examined the characteristics of carnitine transport in primary-cultured rat Sertoli cells, which constitute a part of the blood-testis barrier. Uptake of [3H]carnitine (11.4 nM) from the basal side of Sertoli cells was Na+-dependent and was significantly decreased in the presence of 10 microM (48.0 +/- 7.4% of control) or 100 microM unlabeled carnitine (14.6 +/- 5.7% of control). Furthermore, the uptake was significantly inhibited in the presence of 100 microM acetyl-L-carnitine, 100 microM gamma-butyrobetaine or 500 microM quinidine. In RT-PCR analysis, the high-affinity carnitine transporter OCTN2 was detected in rat whole testis tissue and primary-cultured Sertoli cells. In contrast, the low-affinity carnitine transporter ATB(0,+) was detected in rat whole testis tissue, but not in primary cultured Sertoli cells. These results demonstrate that OCTN2 mediates carnitine supply to Sertoli cells from the circulation.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamasaki, Noda, Chiba 278-8510, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Goto
authors.forename: Tomoji
authors.initials: T
authors.lastname: Maeda
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Nezu
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuji
authors.forename: Ikumi
authors.initials: I
authors.lastname: Tamai
mesh_terms: D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western / Q000379:methods; D002331:Carnitine / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D008297:Male; D027701:Organic Cation Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012708:Sertoli Cells / Q000378:metabolism*; D000074058:Solute Carrier Family 22 Member 5
chemical_list: D027701:Organic Cation Transport Proteins; C115441:Slc22a5 protein, rat; D000074058:Solute Carrier Family 22 Member 5; D012313:RNA; D002331:Carnitine