RT Journal Article
SR Electronic
T1 Isoform Selectivity of 3-<sup>125</sup>I-Iodo-α-Methyl-<span class="sc">l</span>-Tyrosine Membrane Transport in Human L-Type Amino Acid Transporters
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 244
OP 246
VO 44
IS 2
A1 Shikano, Naoto
A1 Kanai, Yoshikatsu
A1 Kawai, Keiichi
A1 Inatomi, Jun
A1 Kim, Do Kyung
A1 Ishikawa, Nobuyoshi
A1 Endou, Hitoshi
YR 2003
UL http://jnm.snmjournals.org/content/44/2/244.abstract
AB 3-123I-Iodo-α-methyl-l-tyrosine (123I-IMT) has been developed for SPECT of amino acid transport imaging. We examined the isoform selectivity of 125I-IMT transport of the 2 human L-type amino acid transporters, hLAT1 and hLAT2, with human 4F2hc-coexpressed Xenopus laevis oocytes. Methods: An uptake study of 125I-IMT was performed using transporter-expressed X. laevis oocytes. Oocytes were injected with 17.6 ng of hLAT1 or hLAT2 complementary RNA (cRNA) and 7.4 ng of h4F2hc cRNA in a molar ratio of 1:1. Two days after injection, the uptake of 125I-IMT was measured in the Na+-free uptake solution containing 18.5 kBq of noncarrier-added 125I-IMT. After incubation for 30 min at room temperature, radioactivity of the oocytes was determined. Results: Of the 2 hLAT isoforms and h4F2hc-coexpressed X. laevis oocytes, 125I-IMT uptake via hLAT1 was 5.95-fold higher than that via hLAT2 (P &lt; 0.005). Conclusion: 125I-IMT transport was hLAT1 selective. Investigations on the isoform selectivity of 125I-IMT transport with other transporters are anticipated.