title: The relationship between antidiuretic hormone and plasma or urine osmolalities during water restriction test and hypertonic saline loading test in normal children--a change in the apparent tubular response to AVP during these two tests.
abstract: We present here the results of water restriction test (WRT) and hypertonic saline loading test (HSLT) in normal children. Maximal urine osmolality during WRT (W-Umax; 1040 +/- 154 mOsm/kg) may be age-dependent (W-Umax = 812 + 23*age, r = 0.52, p < 0.05), although maximal arginine vasopressin (AVP) levels during WRT did not show any correlation with age. The relationship between plasma osmolality (Posm) and AVP during HSLT in children (AVP = 0.31* (Posm-277)) was similar to that in normal adults. A plateau urine osmolality during HSLT (H-Umax) was 713 +/- 109 mOsm/kg. It did not increase with age. AVP levels 3 h after the infusion did not correlate with age. Minimal AVP and Posm values (about 6 pg/ml, 295 mOsm/kg, respectively) for creating H-Umax apparently existed during HSLT. The minimal AVP value (about 6 pg/ml) for H-Umax (during HSLT) was higher than the AVP levels (2.41 +/- 1.37 pg/ml) at W-Umax (during WRT). W-Umax (1040 +/- 154 mOsm/kg) was significantly higher than H-Umax (713 +/- 109 mOsm/kg). Judging from the above comparison of AVP and Uosm (W, H-Umax) at the plateau state of WRT and HSLT in normal children, a change in the apparent tubular response to AVP may be one of the important factors to maintain circulatory volume (CV).
authors.affiliation: Division of Endocrinology and Metabolism, Tokyo Metropolitan Kiyose Children's Hospital, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hasegawa
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001127:Arginine Vasopressin; D001810:Blood Volume; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007677:Kidney Function Tests; D007684:Kidney Tubules / Q000502:physiology*; D008297:Male; D009994:Osmolar Concentration; D011863:Radioimmunoassay; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D014556:Urine; D014868:Water Deprivation
chemical_list: D012462:Saline Solution, Hypertonic; D001127:Arginine Vasopressin