Hayase K, Yoshida A
Department of Home Economics, Aichi University of Education, Japan.
Biosci Biotechnol Biochem. 1995 May;59(5):801-4. doi: 10.1271/bbb.59.801.
The purpose of this study was to find whether the regulation of urea synthesis was mediated through the activation of N-acetyglutamate synthesis by ornithine when the thyroid status was manipulated. Experiments were done on three groups of rats, given 6-propyl-2-thiouracil (PTU, a thyroid inhibitor) without triiodothyronine (T3) treatment, treated with PTU + T3, or neither PTU nor T3 (control). Urinary excretion of urea and the liver concentrations of ornithine and N-acetylglutamate in rats given PTU + T3 were significantly lower than in rats given PTU alone. The liver concentration of N-acetylglutamate was correlated with the liver concentration of ornithine (r = 0.920, p < 0.001). Ornithine administration (0.5 mmol/100 g body wt) elevated the liver concentration of N-acetylglutamate in all three groups. The results suggest that the greater concentration of ornithine in the hypothyroid (PTU alone) rats is likely to increase the N-acetylglutamate concentration in liver and stimulate urea synthesis.
本研究的目的是探究当甲状腺状态受到调控时，尿素合成的调节是否通过鸟氨酸对N-乙酰谷氨酸合成的激活来介导。实验在三组大鼠上进行，分别给予6-丙基-2-硫氧嘧啶（PTU，一种甲状腺抑制剂）且未用三碘甲状腺原氨酸（T3）处理、用PTU + T3处理或既未用PTU也未用T3处理（对照组）。给予PTU + T3的大鼠的尿素尿排泄量以及肝脏中鸟氨酸和N-乙酰谷氨酸的浓度显著低于仅给予PTU的大鼠。肝脏中N-乙酰谷氨酸的浓度与鸟氨酸的肝脏浓度相关（r = 0.920，p < 0.001）。给予鸟氨酸（0.5 mmol/100 g体重）可提高所有三组大鼠肝脏中N-乙酰谷氨酸的浓度。结果表明，甲状腺功能减退（仅给予PTU）大鼠中较高浓度的鸟氨酸可能会增加肝脏中N-乙酰谷氨酸的浓度并刺激尿素合成。
