Characteristics and Regulation of 123I-MIBG Transport in Cultured Pulmonary Endothelial Cells

Characteristics and Regulation of ¹²³I-MIBG Transport in Cultured Pulmonary Endothelial Cells

Kyung-Han Lee, MD¹^,2, Bong-Ho Ko, BS¹^,2, Jin-Young Paik, MS¹, Kyung-Ho Jung, BS¹^,2, Jun-Sang Bae, MS¹^,2, Joon-Young Choi, MD¹, Yearn Seong Choe, PhD¹ and Byung-Tae Kim, MD¹

¹ Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; and ² Center for Molecular Imaging, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

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FIGURE 1. Time course of ¹²³I-MIBG uptake and washout in CPAE cells. (A) ¹²³I-MIBG uptake levels according to duration of incubation, expressed as cellular radioactivity relative to that after 30 min of incubation. (B) ¹²³I-MIBG retention levels according to duration of time in ¹²³I-MIBG-free fresh medium after 30 min of ¹²³I-MIBG uptake, expressed as cellular radioactivity relative to that immediately after medium change. All results represent mean ± SD of triplicate samples from 1 experiment representative of 2 separate experiments.

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FIGURE 2. Representative Western blot for NE transporters. SK-N-SH cells are human neuroblastoma cells used as positive control cells. Molecular masses are given in kilodaltons.

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FIGURE 3. Effects of uptake 1 and uptake 2 inhibitors on CPAE cell ¹²³I-MIBG uptake. Cells were pretreated with uptake 1 inhibitors desipramine, imipramine, and phenoxybenzamine at 0, 1, 50, or 100 µmol/L (A) and with uptake 2 inhibitors corticosterone, clonidine, and normetanephrine at 0, 5, or 50 µmol/L (B) for 30 min and then incubated with ¹²³I-MIBG at 37°C for 30 min. Results are expressed as mean ± SD (triplicate samples) of percent cellular radioactivity relative to that of control cells and are from 1 experiment representative of 3 separate experiments. *P < 0.01. **P < 0.005.

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FIGURE 4. Effects of hypoxia, PMA, and L-NAME on CPAE cell ¹²³I-MIBG uptake. (A) Cells were exposed to 1% oxygen for 0, 0.5, 1, or 4 h and then measured for uptake of ¹²³I-MIBG after 30 min. (B) Cells were preincubated with PMA at 5 and 10 nmol/L or L-NAME at 10 µmol/L and 2 mmol/L for 16 h and then measured for uptake of ¹²³I-MIBG after 30 min. Results are expressed as mean ± SD (triplicate samples) of percent cellular radioactivity relative to that of control cells and are from 1 experiment representative of 2 separate experiments. *P < 0.05. **P < 0.005. ***P < 0.001.