NEONATAL PROXIMAL TUBULAR ACIDIFICATION

糖皮质激素经常用于孕妇以加速 肺成熟，预防呼吸窘迫综合征。的影响 糖皮质激素在发育中的肾脏中的作用尚不清楚。这样做的第一个目的是 建议检查产前糖皮质激素是否会影响 胎兔肾脏的发生。糖皮质激素也被证明可以 在几个器官的成熟过程中起作用。我们计划检查是否 出生后糖皮质激素水平的增加是导致 近端小管成熟性酸化增加和减少 近端小管磷酸盐转运。 早产儿有明显的尿液氯化钠丢失，呈阴性 盐分平衡导致脱水和低钠血症。大部分的氯化钠 成年动物的运输是通过近端小管进行的。然而， 早产儿和足月儿近端肾小管氯化钠转运机制 新生儿是未知的。这项提议的第二个目标是在体外使用 微灌注法研究氯化钠转运的机制和调控 以及这些因素 可能在肾脏发育过程中盐分转运的成熟过程中发挥作用。 该提案的最终目标集中在信号转导系统上 在新生儿近端小管中。几种调节成人的激素 新生儿近端小管运输迟钝或无反应 近端小管。导致信号转导受阻的原因是 未知。我们将研究为什么对甲状旁腺素和多巴胺的反应 在新生儿中减弱，如果糖皮质激素影响成熟 信号转导。

Glucocorticoids are often administered to pregnant women to accelerate lung maturation and prevent respiratory distress syndrome. The effect of glucocorticoids on the developing kidney is unknown. The first aim of this proposal is to examine whether prenatal glucocorticoids affect nephrogenesis in fetal rabbits. Glucocorticoids have also been shown to play a role in the maturation of several organs. We plan to examine if the postnatal increase in glucocorticoid levels are responsible for the maturational increase in proximal tubule acidification and decrease in proximal tubule phosphate transport. Premature neonates have marked urinary losses of NaCl and are in negative salt balance causing dehydration and hyponatremia. The majority of NaCl transport in adult animals is by the proximal tubule. However, the mechanism of proximal tubule NaCl transport by the premature and term neonate is unknown. The second aim of this proposal is to use in vitro microperfusion to examine the mechanism and regulation of NaCl transport and factors which may play a role in maturation of NaCl transport with renal development. The final aim of this proposal focuses on the signal transduction system in neonatal proximal tubule. Several hormones which regulate adult proximal tubule transport have a blunted or no response in the neonatal proximal tubule. The reason, for this block in signal transduction is unknown. We will examine why the response to PTH and dopamine are attenuated in the neonate and if glucocorticoids affect the maturation of signal transduction.