Isoform Selectivity of 3-125I-Iodo-α-Methyl-l-Tyrosine Membrane Transport in Human L-Type Amino Acid Transporters

Journal of Nuclear Medicine

Do Kyung Kim¹  Jun Inatomi¹  Nobuyoshi Ishikawa¹  Naoto Shikano¹  Hitoshi Endou¹  Yoshikatsu Kanai¹  Keiichi Kawai¹ 

关键词: membrane transport;    3-¹²⁵I-iodo-α-methyl-l-tyrosine;    human L-type amino acid transporter family;    human 4F2hc;    Xenopus laevis oocyte;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

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 < 0.005). Conclusion: 125I-IMT transport was hLAT1 selective. Investigations on the isoform selectivity of 125I-IMT transport with other transporters are anticipated.

【 授权许可】

Unknown