Ontogenetic and Phylogenelic anaylses of factors affecting the developmental process in crine concentrating mechanism

在我们以前的研究中，我们证明了新生儿肾髓质的肾小管功能从“鸟型”转变为“鸟型”组织。这些变化包括在Henle袢的细升支中主动NaCl重吸收的消失和大的被动NaCl重吸收的出现，以及在细降支中通过AQP-1的水渗透性的出现。为了阐明肾髓质的尿浓缩系统的变化机制，我们研究了妊娠期延长的影响，从而考察生育对制度转型变化的影响。通过两种方法延长妊娠。一种方法是在怀孕第17天进行阴道结扎。另一种方法是给予孕鼠孕酮。这两种方法都使我们的妊娠期延长了3天。当我们比较3天新生儿和23天胎儿的Henle袢细升支的成熟时，肾髓质NKCC 2免疫反应性的消失和细升支的正性跨上皮电压的减少是相似的，这些结果强烈地表明肾髓质尿的转化性变化是由肾髓质的细胞膜上的细胞膜在出生过程中发生的集中系统不是依赖于出生本身的过程，而是肾脏发育过程中的程序化过程。

In our previous investigation, we demonstrated that the neonatal renal medulla is transformed from 'avian-type' to 'mammalian-type' organization of the renal tubular functions. The transformations include the disappearance of active NaCl reabsorption and emergence of large passive NaCl reabsorption in the thin ascending limb of Henle's loop, and appearance of water permeability via AQP-1 in the thin descending limb.To elucidate the mechanism of transformation in the urine concentrating system of the renal medulla, we investigated the effect of elongation of the pregnancy period, thereby examining the influence of the birth on the transformational change in the system. The prolongation of pregnancy was achieved by two methods. One method is the vaglnal ligation on the day 17 during pregnancy. Another method is the administration of progesterone to the pregnant rats. Both methods enebled us to elongate the period of pregnancy by 3 days.When we compared the maturation of the thin ascending limb of Henle's loop between day3 neonates and day 23 fetuses, the disappearance of NKCC2 immunoreactivity in the renal medulla and diminishment of the positive transepithelial voltages in the thin ascending limb were similar.These results strongly suggest that the transformational changes of the renal medullary urine concentrating system occurring during the birth is not the process dependent on the birth itself, but the process programmed in the developmental process of the kidneys.