van der Heide D, Ende-Visser M P
Acta Endocrinol (Copenh). 1980 Apr;93(4):448-54. doi: 10.1530/acta.0.0930448.
A very sensitive radioimmunoassay for reverse T3 in rat plasma is described. The concentrations of T4, T3 and reverse T3 in plasma of male and female rats were determined during the first 3 months of life. T4 concentrations reached a maximum value of 5.2 +/- 0.7 microgram/100 ml (mean +/- SD) when the rats were about 16 days old. As of day 28 the average serum T4 was approximately 4 microgram/100 ml. Concentrations of T3 reached a maximum value of 168 +/- 34 ng/100 ml (mean +/- SD) during the 16-20 day period. A plateau value of about 40 ng/100 ml was maintained after about 70 days. For reverse T3 a maximum value of 17.1 +/- 4.2 ng/100 ml (mean +/- SD) was found in rats between 13 and 16 days old, followed by a steep decrease to 8.2 +/- 0.9 ng/100 ml around the 28th day and a subsequent continuous slow increase. For the T3/reverse T3 ration (as a parameter of the direction of the conversion pathway) the highest value of 16 was found during the fourth week of life. After 70 days the T3/ reverse T3 ratio was only 3.5. The reciprocal fluctuations between T3 and reverse T3, as found in man and sheep, are less pronounced in the rat. The very high metabolic clearance rate of reverse T3 compared to that of T3 could be the explanation.
本文描述了一种用于测定大鼠血浆中反三碘甲状腺原氨酸（reverse T3）的高灵敏度放射免疫分析方法。在雄性和雌性大鼠出生后的前3个月内，测定了其血浆中甲状腺素（T4）、三碘甲状腺原氨酸（T3）和反三碘甲状腺原氨酸的浓度。当大鼠约16日龄时，T4浓度达到最大值5.2±0.7微克/100毫升（平均值±标准差）。从第28天起，血清T4平均约为4微克/100毫升。T3浓度在16 - 20日龄期间达到最大值168±34纳克/100毫升（平均值±标准差）。约70天后维持在约40纳克/100毫升的平台值。对于反三碘甲状腺原氨酸，在13至16日龄的大鼠中发现最大值为17.1±4.2纳克/100毫升（平均值±标准差），随后在第28天左右急剧下降至8.2±0.9纳克/100毫升，随后持续缓慢上升。对于T3/反三碘甲状腺原氨酸比值（作为转换途径方向的参数），在出生后第四周发现最高值为16。70天后，T3/反三碘甲状腺原氨酸比值仅为3.5。在人和绵羊中发现的T3和反三碘甲状腺原氨酸之间的相互波动在大鼠中不太明显。与T3相比，反三碘甲状腺原氨酸的代谢清除率非常高可能是其原因。
