Ikeda Kunishige, Hisada Aya, Otake Takamitsu, Omagari Ryo, Nakajima Daisuke, Kato Nobumasa, Yoshinaga Jun
Faculty of Life Sciences, Toyo University, 48-1 Oka, Asaka, Saitama 351-8510, Japan.
Center for Preventive Medical Sciences, Chiba University, 1-33 Yayoi cho, Inage, Chiba 263-8522, Japan.
Toxics. 2025 Mar 14;13(3):213. doi: 10.3390/toxics13030213.
Fipronil, a widely used phenylpyrazole insecticide, is known to disrupt circulating thyroid hormone (TH) levels in rodents. Concentrations of fipronil and its metabolites (fipronil sulfone and fipronil sulfide) in serum samples collected in 2009-2011 were measured for 131 Japanese pregnant women by a sensitive and accurate liquid chromatography-tandem mass spectrometric method developed in our laboratory to relate TH levels. Fipronil sulfone was detected in all the subjects with the median being 21 ng/L (min-max: 6.8-89), but fipronil and fipronil sulfide were detected in none of the subjects (detection limit: 5.0 and 1.2 ng/L, respectively), indicating a rapid and exclusive oxidative conversion to fipronil sulfone upon exposure. The median concentration of fipronil sulfone was lower than those previously reported for general populations in other countries by one order of magnitude. There were no attributes or dietary habits of the subjects that significantly vary the serum fipronil sulfone concentrations. Multiple regression analyses found no significant association between serum concentrations of fipronil sulfone and free thyroxine- or thyroid-stimulating hormone levels, indicating the absence of adverse effects on circulating TH levels probably due to the lower exposure levels of the present subjects. The present result would be valuable for establishing a dose-effect relationship of fipronils in humans on population levels.
氟虫腈是一种广泛使用的苯基吡唑类杀虫剂，已知会扰乱啮齿动物体内循环甲状腺激素（TH）的水平。本实验室开发了一种灵敏且准确的液相色谱 - 串联质谱法，用于测定2009 - 2011年收集的131名日本孕妇血清样本中氟虫腈及其代谢物（氟虫腈砜和氟虫腈硫醚）的浓度，以关联TH水平。所有受试者均检测到氟虫腈砜，中位数为21 ng/L（最小值 - 最大值：6.8 - 89），但未在任何受试者中检测到氟虫腈和氟虫腈硫醚（检测限分别为5.0和1.2 ng/L），这表明暴露后氟虫腈会迅速且专一性地氧化转化为氟虫腈砜。氟虫腈砜中位数浓度比其他国家先前报道的普通人群低一个数量级。受试者的任何特征或饮食习惯均未使血清氟虫腈砜浓度产生显著差异。多元回归分析发现，血清氟虫腈砜浓度与游离甲状腺素或促甲状腺激素水平之间无显著关联，这表明可能由于本研究对象的暴露水平较低，故而对循环TH水平不存在不良影响。本研究结果对于在人群水平上建立氟虫腈在人体内的剂量 - 效应关系具有重要价值。
