Bonilla-Felix M, Vehaskari V M, Hamm L L
Department of Pediatrics, University of Texas-Health Science Center at Houston 77030, USA.
Pediatr Nephrol. 1999 Feb;13(2):103-7. doi: 10.1007/s004670050572.
Immature animals have limited ability to concentrate the urine. This is in part the result of end-organ resistance to arginine vasopressin (AVP). To characterize this response, we measured water absorption in microperfused cortical collecting ducts (iCCD) and outer medullary CD (iOMCD) derived from 2- to 12-day-old rabbits. The roles of adenosine 3',5'-cyclic monophosphate (cAMP) and prostaglandins were investigated. Baseline osmotic water permeability (L(p), 10(-7) cm/atm per s) in the iCCD (20.3+/-2.4) and iOMCD (19.7+/-5.6) was not different from mature CCD (mCCD) (14.6+/-3.1). After AVP, L(p) in the iCCD (46.7+/-10.0) was significantly lower than in the mCCD (114.3+/-21.8). Neither stimulation with cAMP (85.6+/-51.3) nor inhibition of endogenous prostaglandin production with indomethacin (57.6+/-29.8) abolished the blunted response to AVP in the iCCD. We conclude that AVP-stimulated water transport in the iCCD is impaired. The disruption in AVP response is, at least in part, localized distal to cAMP, and is not mediated by prostaglandins.
未成熟动物浓缩尿液的能力有限。这部分是终末器官对精氨酸加压素（AVP）抵抗的结果。为了描述这种反应，我们测量了来自2至12日龄兔子的微灌注皮质集合管（iCCD）和外髓集合管（iOMCD）的水吸收。研究了3',5'-环磷酸腺苷（cAMP）和前列腺素的作用。iCCD（20.3±2.4）和iOMCD（19.7±5.6）的基线渗透水通透性（L(p)，10^(-7) cm/atm per s）与成熟集合管（mCCD）（14.6±3.1）没有差异。给予AVP后，iCCD的L(p)（46.7±10.0）显著低于mCCD（114.3±21.8）。用cAMP刺激（85.6±51.3）或用吲哚美辛抑制内源性前列腺素生成（57.6±29.8）均未消除iCCD对AVP反应的减弱。我们得出结论，AVP刺激的iCCD水转运受损。AVP反应的破坏至少部分定位于cAMP的远端，且不是由前列腺素介导的。
