Department of Internal Medicine, Division of Endocrinology, Radboud University Medical Center, Geert Grooteplein Zuid 8, 6525 GA, Nijmegen, The Netherlands.
Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 8, 6525 GA, Nijmegen, The Netherlands.
Sci Rep. 2019 Apr 1;9(1):5396. doi: 10.1038/s41598-019-41997-2.
Sufficient thyroid iodine uptake is needed to ensure effective radioactive iodine (RAI) treatment, which is mediated by the sodium-iodide symporter (NIS). Activation of AMP-activated-protein-kinase (AMPK), leads to decreased NIS expression and thyroid iodine uptake in in vitro and animal models. Clinically relevant conditions that lead to AMPK activation include metformin use and hypocaloric conditions. Here, we aim to assess the effects of metformin and hypocaloric diet on thyroid iodine uptake in healthy volunteers. Healthy male volunteers were included and randomized. Group 1 (n = 8) received metformin, group 2 (n = 7) followed a hypocaloric diet (1500 kcal/day), superposed on a moderate iodine restriction diet; Baseline measurements included thyroid iodine-123 (I-123) uptake and TSH, fT4, T3 and rT3 levels. After two weeks, thyroid function and I-123 uptake measurements were repeated. Baseline characteristics were similar between groups. Levels of TSH and fT4 were similar after each intervention. T3 decreased after hypocaloric diet and metformin (-0.2 ± 0.19 nmol/L, p = 0.0327; respectively -0.13 ± 0.13 nmol/L, p = 0.0282), resulting in decreased T3/rT3 ratios. There was no significant difference in thyroid I-123 uptake after each intervention. In conclusion, metformin treatment and hypocaloric diet resulted in a significant decrease in T3 levels and T3/rT3 ratios in healthy volunteers, without significant effects on thyroid iodine uptake. We found no indications that metformin or hypocaloric diet will have clinically relevant effects on RAI uptake.
需要有足够的甲状腺碘摄取量才能确保放射性碘（RAI）治疗有效，而这是由钠碘同向转运体（NIS）介导的。在体外和动物模型中，激活 AMP 激活的蛋白激酶（AMPK）会导致 NIS 表达和甲状腺碘摄取减少。导致 AMPK 激活的临床相关情况包括使用二甲双胍和低热量条件。在这里，我们旨在评估二甲双胍和低热量饮食对健康志愿者甲状腺碘摄取的影响。纳入了健康男性志愿者并进行了随机分组。第 1 组（n=8）接受二甲双胍治疗，第 2 组（n=7）遵循低热量饮食（每天 1500 卡路里），同时限制碘摄入；基线测量包括甲状腺碘-123（I-123）摄取和 TSH、fT4、T3 和 rT3 水平。两周后，重复测量甲状腺功能和 I-123 摄取。两组的基线特征相似。每个干预后的 TSH 和 fT4 水平相似。低热量饮食和二甲双胍治疗后 T3 下降（分别为-0.2±0.19 nmol/L，p=0.0327；-0.13±0.13 nmol/L，p=0.0282），导致 T3/rT3 比值降低。每个干预后甲状腺 I-123 摄取无显著差异。结论：二甲双胍治疗和低热量饮食导致健康志愿者 T3 水平和 T3/rT3 比值显著降低，但对甲状腺碘摄取无显著影响。我们没有发现二甲双胍或低热量饮食会对 RAI 摄取产生临床相关影响的迹象。
