OCTN2-mediated transport of carnitine in isolated Sertoli cells.
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.
Kobayashi
Daisuke
D
Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamasaki, Noda, Chiba 278-8510, Japan.
Goto
Akihiko
A
Maeda
Tomoji
T
Nezu
Jun-Ichi
J
Tsuji
Akira
A
Tamai
Ikumi
I
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
D027701:Organic Cation Transport Proteins; C115441:Slc22a5 protein, rat; D000074058:Solute Carrier Family 22 Member 5; D012313:RNA; D002331:Carnitine