Programade Pós-Graduação em Ciências Biológicas Bioquímica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Campus Universitário, Camobi, Rio Grande do Sul, Brasil.
Universidade Federal de Pelotas, Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Curso de Farmácia, Pelotas, Rio Grande do Sul, Brasil.
J Cell Biochem. 2018 Jul;119(7):6249-6257. doi: 10.1002/jcb.26856. Epub 2018 Apr 16.
The purinergic system has an important role in the regulation of vascular functions. The interference of thyroid hormones in this system and in cardiovascular events has been studied in recent years. However, the mechanisms involved in vascular, purinergic, and oxidative changes in thyroid disorders are not completely understood. Therefore, the present study aimed to assess purinergic enzyme activity in platelets from rats with hypothyroidism and hyperthyroidism induced, respectively, by continuous exposure to methimazole (MMI) at 20 mg/100 mL or L-thyroxine at 1.2 mg/100 mL in drinking water for 1 month. Results showed that rats exposed to L-thyroxine had a significant decrease in NTPDase activity, wherein ATP hydrolysis was 53% lower and ADP hydrolysis was 40% lower. Moreover, ecto-5'-nucleotidase activity was decreased in both groups, by 39% in the hypothyroidism group and by 52% in the hyperthyroidism group. On the other hand, adenosine deaminase (ADA) activity was increased in hyperthyroidism (75%), and nucleotide pyrophosphatase/phosphodiesterase (NPP) activity was increased in animals with hypothyroidism (127%) and those with hyperthyroidism (128%). Our findings suggest that changes in purinergic enzyme and purine levels could contribute to the undesirable effects of thyroid disturbances. Moreover, oxidative stress and, in particular, a high level of ROS production, showed a causal relation with changes in ectonucleotidase activity and nucleotide and nucleoside levels.
嘌呤能系统在调节血管功能方面具有重要作用。近年来，人们研究了甲状腺激素对该系统和心血管事件的干扰。然而，甲状腺功能紊乱时血管、嘌呤能和氧化变化的相关机制尚未完全阐明。因此，本研究旨在评估分别用持续暴露于甲巯咪唑（MMI）（20mg/100mL）或左甲状腺素（1.2mg/100mL）于饮用水中 1 个月诱导的甲状腺功能减退症和甲状腺功能亢进症大鼠血小板中的嘌呤能酶活性。结果显示，暴露于左甲状腺素的大鼠 NTPDase 活性显著降低，其中 ATP 水解降低了 53%，ADP 水解降低了 40%。此外，两组的外切 5'-核苷酸酶活性均降低，甲状腺功能减退组降低 39%，甲状腺功能亢进组降低 52%。另一方面，甲状腺功能亢进症大鼠的腺苷脱氨酶（ADA）活性升高（75%），甲状腺功能减退症大鼠（127%）和甲状腺功能亢进症大鼠（128%）的核苷酸焦磷酸酶/磷酸二酯酶（NPP）活性升高。我们的研究结果表明，嘌呤能酶和嘌呤水平的变化可能导致甲状腺功能紊乱的不良影响。此外，氧化应激，特别是 ROS 产生水平升高，与外切核苷酸酶活性和核苷酸及核苷水平的变化存在因果关系。
