In vivo and in vitro binding of [
<sup>125</sup>
I]I‐R‐(+)‐TISCH: A dopamine D
<sub>1</sub>
receptor ligand for studying pancreatic β‐cell mass
作者:Yan Zhang、Guangwen Li、Yuli Sun、Haiyan Hong、Linlin Li、Yang Luo、Ran Wang、Lin Zhu、Hank F. Kung、Jinxia Zhu
DOI:10.1002/jlcr.4005
日期:2022.12
Diabetes mellitus (DM) and insulinoma are mainly affected by the status of pancreatic β-cell mass (BCM). Development of imaging agents for BCM allows to study pancreatic β cells and the relationship between β cells and DM or insulinoma. In this study, we investigated the density of dopamine D1 receptor on the β cells and measured BCM by statistical image processing. The pancreatic uptakes of [125I]I-R-(+)-7-chloro-8-hydroxy-1-(3′-iodopheny1)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine ([125I]I-R-(+)-TISCH), dopamine D1 receptor tracer, in normal and diabetic rats displayed significant differences at 30 min (1.11 ± 0.08% ID/g vs. 0.63 ± 0.09% ID/g, p < 0.0001). In the presence of SCH23390, the pancreatic uptake of [125I]I-R-(+)-TISCH at 30 min in normal rats was lower (1.01 ± 0.04% ID/g, p < 0.05). Although the blocking was not complete, [125I]I-R-(+)-TISCH showed specific binding signals to the pancreas. Furthermore, the uptakes of [125I]I-R-(+)-TISCH in INS-1 cells were reduced in the presence of SCH23390 at different concentrations. [125I]I-R-(+)-TISCH displayed a respectable uptake in insulinoma. Overall, [125I]I-R-(+)-TISCH provided specific binding signals to pancreatic β cells. Although the specific signal may not be sufficient for imaging in vivo, the dopamine D1 receptor can still be considered as a potential target for studying BCM. Further investigation will be required to optimize the ligand.
糖尿病(DM)和胰岛素瘤主要受胰腺β细胞团(BCM)状态的影响。BCM成像剂的开发有助于研究胰腺β细胞以及β细胞与DM或胰岛素瘤之间的关系。在这项研究中,我们研究了β细胞上多巴胺D1受体的密度,并通过统计图像处理测量了BCM。正常大鼠和糖尿病大鼠对多巴胺D1受体示踪剂[125I]I-R-(+)-7-氯-8-羟基-1-(3′-碘苯基1)-3-甲基-2,3,4,5-四氢-1H-3-苯并氮杂卓([125I]I-R-(+)-TISCH)的胰腺摄取量在30分钟时有显著差异(1.11 ± 0.08% ID/g vs. 0.63 ± 0.09% ID/g, p < 0.0001)。在 SCH23390 的存在下,正常大鼠胰腺在 30 分钟内对 [125I]I-R-(+)-TISCH 的摄取较低(1.01 ± 0.04% ID/g,p < 0.05)。虽然阻断并不完全,但[125I]I-R-(+)-TISCH 显示了与胰腺的特异性结合信号。此外,在不同浓度的 SCH23390 存在下,INS-1 细胞对[125I]I-R-(+)-TISCH 的吸收均有所减少。胰岛素瘤对[125I]I-R-(+)-TISCH的摄取量相当可观。总之,[125I]I-R-(+)-TISCH 提供了与胰岛β细胞的特异性结合信号。虽然特异性信号可能不足以进行体内成像,但多巴胺 D1 受体仍可被视为研究 BCM 的潜在靶点。优化配体还需要进一步的研究。