Yoshida K, Suzuki M, Sakurada T, Kitaoka H, Kaise N, Kaise K, Fukazawa H, Nomura T, Yamamoto M, Saito S
Acta Endocrinol (Copenh). 1984 Dec;107(4):495-9. doi: 10.1530/acta.0.1070495.
Monodeiodination of thyroxine (T4) was studied in the liver, kidney and placenta of pregnant rats. Age matched female non-pregnant and pregnant Sprague-Dawley rats on the 7th, 14th, 17th and 21st days of gestation were used. The 800 X g supernatants of tissue homogenates (protein 1 mg/tube) were incubated with 1 microgram of stable T4 in the presence of 5 mM dithiothreitol (DTT) at 37 degrees C for 60 min at pH 7.5. Net triiodothyronine (T3) generation from T4 in rat liver homogenates on the 7th day of gestation was significantly lower than that in the non-pregnant rat. Thereafter it increased, but values on the 14th, 17th and 21st days of gestation were not significantly different from those obtained in the non-pregnant rat. Net renal T3 generation from T4 on the 14th day was significantly lower than that in the non-pregnant rat. It was increased thereafter and the values at the 17th and 21st days of gestation were not significantly different from those in the non-pregnant rat. Net reverse T3 (rT3) generation from T4 in the placenta rose from the 14th to the 17th day and then dropped by the 21st day and the value at the 17th day was significantly higher than those at the 14th and 21st days of gestation. These results indicate that 1) both T4 outer-ring monodeiodination in the pregnant rat liver and kidney, and T4 inner-ring monodeiodination in the placenta show significant variation with the progress of gestation; 2) the time course of the T4 outer-ring monodeiodination in pregnant rat liver and kidney is completely different from T4 inner-ring monodeiodination in the placenta.
对妊娠大鼠的肝脏、肾脏和胎盘进行甲状腺素（T4）单碘脱碘作用的研究。选用年龄匹配的雌性未孕和妊娠的斯普拉格-道利大鼠，分别处于妊娠第7、14、17和21天。将组织匀浆的800×g上清液（蛋白质1mg/管）与1μg稳定的T4在5mM二硫苏糖醇（DTT）存在下，于37℃、pH7.5孵育60分钟。妊娠第7天大鼠肝脏匀浆中由T4净生成的三碘甲状腺原氨酸（T3）显著低于未孕大鼠。此后有所增加，但妊娠第14、17和21天的值与未孕大鼠获得的值无显著差异。妊娠第14天肾脏由T4净生成的T3显著低于未孕大鼠。此后增加，妊娠第17和21天的值与未孕大鼠无显著差异。胎盘由T4净生成的反三碘甲状腺原氨酸（rT3）从第14天升至第17天，然后在第21天下降，第17天的值显著高于妊娠第14和21天。这些结果表明：1）妊娠大鼠肝脏和肾脏中T4外环单碘脱碘以及胎盘T4内环单碘脱碘均随妊娠进程呈现显著变化；2）妊娠大鼠肝脏和肾脏中T4外环单碘脱碘的时间进程与胎盘T4内环单碘脱碘完全不同。
