Water transport in the immature rabbit collecting duct.
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.
Bonilla-Felix
M
M
Department of Pediatrics, University of Texas-Health Science Center at Houston 77030, USA.
Vehaskari
V M
VM
Hamm
L L
LL
D000465:Algorithms; D000818:Animals; D000831:Animals, Newborn; D001127:Arginine Vasopressin / Q000494:pharmacology; D001693:Biological Transport, Active; D001834:Body Water / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007671:Kidney Concentrating Ability; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D010477:Perfusion; D011453:Prostaglandins / Q000096:biosynthesis; D011817:Rabbits; D012076:Renal Agents / Q000494:pharmacology
D016861:Cyclooxygenase Inhibitors; D011453:Prostaglandins; D012076:Renal Agents; D001127:Arginine Vasopressin; D000242:Cyclic AMP; D007213:Indomethacin