ONTOGENESIS OF THYROID-FUNCTION IN NEONATAL RAT - THYROXINE (T4) AND TRIIODOTHYRONINE (T3) PRODUCTION-RATES
ONTOGENESIS OF THYROID-FUNCTION IN NEONATAL RAT - THYROXINE (T4) AND TRIIODOTHYRONINE (T3) PRODUCTION-RATES
复制标题
DOI：
10.1210/endo-101-2-435
复制
发表时间：
1977-01-01
期刊：
影响因子：
4.8
通讯作者：
DUSSAULT, JH
中科院分区：
文献类型：
--
作者：
DUBOIS, JD;DUSSAULT, JH
用单室分析法测定[125 I] T_4和[125 I] T_3的动力学参数，研究了新生大鼠（从5天到成年）甲状腺素（T_4）和三碘甲状腺原氨酸（T_3）产生的个体发生。用特异性放射免疫法测定血清T4和T3浓度。T4的分布容积（VD）和代谢清除率（MCR）在第5天时较高，在第22-26天时增加至峰值，并下降至成人值。T_4产生率（PR）在5日龄时较低，14-32日龄时达到峰值，然后下降至成虫值。从出生到成年，T4分数去除率（K）相似。在大鼠的一生中，未观察到T3的K、VD和MCR的差异。T3 PR从第5天的最小值上升至第26天的峰值。T4 PR峰值与T3 PR峰值之间约有12天的延迟，T4/T3 PR比值从第5天的最大值下降到第12天接近成人的值。由于T3 PR增加，T4 PR在26天时恢复到成人值之前显著升高，因此在14天时出现显著升高。T4 PR峰值后T3 PR增加可能代表外周T4单脱碘至T3增加，可能类似于绵羊和人类出生后T3的显著升高。这些数据证实，甲状腺激素分泌的个体发育发生在大鼠出生后，并表明大鼠生命的前20天可能对应于人类胎儿妊娠的最后三个月。
The ontogenesis of thyroxine (T4) and triiodothyronine (T3) production in the neonatal rat (from 5 days to adulthood) was examined by measuring [125I]T4 and [125I]T3 kinetic parameters by single-compartmental analysis. T4 and T3 serum concentrations were measured by specific radioimmunoassay. The volume of distribution (VD) and the metabolic clearance rate (MCR) of T4, high at 5 days, increase to a peak at 22-26 days and decline to adult values. The T4 production rate (PR) low at 5 days, increases to peak values at 14-32 days and then declines toward adult values. The T4 fractional removal rate (K) is similar from birth to adulthood. No difference is observed for K, VD and MCR of T3 during the life of the rat. The T3 PR rises from minimal values at 5 days to attain peak values at 26 days. There is a delay of about 12 days between the peak of T4 PR and the attainment of the peak T3 PR. The T4/T3 PR ratio decreases from a maximal value at 5 days to values approaching those seen in the adult at 12 days. There is a significant rise at 14 days due to the marked rise in the T4 PR before the ratio returns to adult values by 26 days as a result of the increase in the T3 PR. The increasing T3 PR following the peak in the T4 PR may represent increasing peripheral T4 monodeiodination to T3 and may be analogous to the marked rise in T3 following birth in the sheep and human. These data confirm that the ontogenesis of thyroid hormone secretion occurs after birth in the rat and suggest that the first 20 days of life in the rat may correspond to the last trimester of gestation of the human fetus.