Zanjani E D
Exp Hematol. 1980;8 Suppl 8:29-40.
The liver to kidney switch of erythropoietin (Ep) formation was studied in sheep. The switch was initiated in utero during the last third of the gestation period, and was completed by about 40 days after birth. Administration of testosterone or estradiol benzoate to the fetus/newborn resulted in significant changes in the erythropoietic status of the animal, but failed to affect the initiation and/or completion of the switch. In contrast, a significant delay in the start of the switch occurred in thyroidectomized and chronically anemic fetus-newborns. Treatment of the thyroidectomized animals with thyroxin prevented the delay but accelerated the rate at which the switch was completed. These results demonstrate that 1) the transition from the liver to the kidney is initiated in utero by mechanisms which are independent of sex hormonal influences, 2) the acquisition of the Ep-producing capacity by kidneys is accompanied by a gradual decrease in liver Ep formation, and not by a sudden loss of hepatic Ep production, and 3) the onset and/or progression of the liver to kidney switch is profoundly influenced by the functional status of the thyroid gland and by changes in the oxygen supply-demand ratio.
在绵羊身上研究了促红细胞生成素（Ep）形成从肝脏到肾脏的转换。这种转换在孕期最后三分之一时于子宫内启动，并在出生后约40天完成。给胎儿/新生儿注射睾酮或苯甲酸雌二醇会导致动物造血状态发生显著变化，但未能影响转换的启动和/或完成。相比之下，甲状腺切除的慢性贫血胎儿-新生儿转换开始出现显著延迟。用甲状腺素治疗甲状腺切除的动物可防止延迟，但加快了转换完成的速度。这些结果表明：1）从肝脏到肾脏的转换在子宫内由独立于性激素影响的机制启动；2）肾脏获得产生Ep的能力伴随着肝脏Ep形成的逐渐减少，而非肝脏Ep产生的突然丧失；3）从肝脏到肾脏的转换的开始和/或进展受到甲状腺功能状态以及氧供需比变化的深刻影响。
