TY - JOUR
T1 - Renal water channel expression in newborns
T2 - Measurement of urinary excretion of aquaporin-2
AU - Tsukahara, Hirokazu
AU - Hata, Ikue
AU - Sekine, Kyoichi
AU - Miura, Masakazu
AU - Kotsuji, Fumikazu
AU - Mayumi, Mitsufumi
N1 - Funding Information:
From the Departments of Pediatrics and Gynecology and Obstetrics, Fukui Medical School, Fukui; and Department of Research and Development, Mitsubishi Kagaku Bio-Clinical Laboratories, Tokyo, Japan. Submitted October 6, 1997; accepted May 13, 1998. Supported in part by a research grant from the National Children's Hospital, Tokyo, Japan. Address reprint requests to Hirokazu Tsukahara, MD, Department of Pediatrics, Fukui Medical School, Fukui 910-11, Japan. Copyright © 1998 by W.B. Saunders Company 0026-0495/98/4711-0008503. 00/(9
PY - 1998
Y1 - 1998
N2 - Aquaporin-2 (AQP-2) encodes the vasopressin-regulated 'water channels' of the renal collecting duct and is excreted in human urine. We measured urinary excretion of AQP-2 by radioimmunoassay in 15 term and 10 preterm infants on day 1 and day 4 of life to determine the molecular basis of water balance during the newborn period. AQP-2 was detectable in the urine of term and preterm newborns, but AQP-2 excretion was severalfold less than the reported level in normal adults. Urinary excretion of AQP-2 significantly decreased postnatally, in parallel with a reduction in urine osmolality and arginine vasopressin (AVP) excretion. Urinary AQP-2 correlated positively and significantly with urine osmolality on days 1 and 4 and with AVP on day I in both groups. No significant differences were detected in AQP-2 levels between term and preterm newborns. Our findings suggest that vasopressin-regulated water channels are expressed in the renal collecting duct of both term and preterm newborns, although to a lesser extent as compared with adults, and these channels encoded by AQP-2 contribute to the urine concentrating power of the newborn kidney.
AB - Aquaporin-2 (AQP-2) encodes the vasopressin-regulated 'water channels' of the renal collecting duct and is excreted in human urine. We measured urinary excretion of AQP-2 by radioimmunoassay in 15 term and 10 preterm infants on day 1 and day 4 of life to determine the molecular basis of water balance during the newborn period. AQP-2 was detectable in the urine of term and preterm newborns, but AQP-2 excretion was severalfold less than the reported level in normal adults. Urinary excretion of AQP-2 significantly decreased postnatally, in parallel with a reduction in urine osmolality and arginine vasopressin (AVP) excretion. Urinary AQP-2 correlated positively and significantly with urine osmolality on days 1 and 4 and with AVP on day I in both groups. No significant differences were detected in AQP-2 levels between term and preterm newborns. Our findings suggest that vasopressin-regulated water channels are expressed in the renal collecting duct of both term and preterm newborns, although to a lesser extent as compared with adults, and these channels encoded by AQP-2 contribute to the urine concentrating power of the newborn kidney.
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U2 - 10.1016/S0026-0495(98)90302-X
DO - 10.1016/S0026-0495(98)90302-X
M3 - Article
C2 - 9826210
AN - SCOPUS:0031783687
SN - 0026-0495
VL - 47
SP - 1344
EP - 1347
JO - Metabolism: Clinical and Experimental
JF - Metabolism: Clinical and Experimental
IS - 11
ER -
