NEONATAL PROXIMAL TUBULAR ACIDIFICATION

糖皮质激素常用于孕妇， 肺成熟和预防呼吸窘迫综合征。的影响 糖皮质激素对发育中的肾脏的影响尚不清楚。第一个目标是 建议检查产前糖皮质激素是否影响 胎兔肾发生。糖皮质激素也被证明 在几个器官的成熟中发挥作用。我们计划研究 出生后糖皮质激素水平的增加是导致 近端小管酸化的成熟增加和 近曲小管磷酸盐转运。 早产儿有明显的尿中NaCl丢失， 盐平衡导致脱水和低钠血症。大多数NaCl 在成年动物中通过近端小管转运。但 早产儿和足月儿近曲小管NaCl转运的机制 新生儿不详。该提案的第二个目的是在体外使用 微灌流，以研究NaCl转运的机制和调节 以及 可能在肾脏发育过程中NaCl转运的成熟中起作用。 本提案的最终目的集中在信号转导系统 在新生儿近端小管中。几种调节成人的激素 新生儿近端小管转运反应迟钝或无反应 近端小管信号传导受阻的原因是 未知我们将研究为什么对PTH和多巴胺的反应是 在新生儿中减弱，如果糖皮质激素影响 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.