Intraamniotic deamino(D-Arg8)-vasopressin: prolonged effects on ovine fetal urine flow and swallowing.
OBJECTIVE
Fetal urine is the main source of amniotic fluid, and alterations in urine production have an impact on amniotic fluid dynamics. Intraamniotic arginine vasopressin is absorbed into fetal plasma, but fetal antidiuretic responses may be obscured by vasoconstrictor (V1 receptor) actions of arginine vasopressin. We determined the effects of intraamniotic administration of a specific V2 receptor agonist, deamino(D-Arg8)-vasopressin, on fetal plasma arginine vasopressin immunoreactivity, fetal urine output, and swallowing.


METHODS
Six chronically prepared pregnant ewes (129 +/- 1 days' gestation) received a single deamino(D-Arg8) (50 micrograms injection into the amniotic fluid with subsequent measurement of fetal plasma arginine vasopressin immunoreactivity, fetal urine flow and osmolality, and fetal swallowing.


RESULTS
Within 30 minutes of deamino(D-Arg8)-vasopressin administration, fetal plasma arginine vasopressin immunoreactivity (4.5 +/- 0.5 to 76.4 +/- 21.9 pg/ml) and urine osmolality (135 +/- 13 to 285 +/- 43 mOsm/kg H2O) significantly increased and urine flow decreased (0.18 +/- 0.01 to 0.05 +/- 0.01 ml/kg per minute). After 48 hours urine flow remained reduced (0.08 +/- 0.03 mg/kg per minute) and osmolality remained elevated (399 +/- 18 mOsm/kg H2O). There were no changes in fetal swallowing, systolic (64 +/- 3 mm Hg) or diastolic (42 +/- 3 mm Hg) blood pressure, or heart rate (169 +/- 6 beats/min).


CONCLUSIONS
Intraamniotic deamino(D-Arg8)-vasopressin administration evokes persistent fetal antidiuresis in the absence of arginine vasopressin-induced fetal cardiovascular effects or changes in fetal swallowed volume, indicating its suitability as a potential therapeutic agent in amniotic fluid volume disorders such as polyhydramnios.
Kullama
L K
LK
Perinatal Research Laboratory, Harbor-University of California, Los Angeles Medical Center, Los Angeles School of Medicine, Torrance 90502, USA.
Nijland
M J
MJ
Ervin
M G
MG
Ross
M G
MG
D000653:Amniotic Fluid; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage / Q000494:pharmacology*; D003679:Deglutition / Q000187:drug effects*; D004231:Diuresis / Q000187:drug effects*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005333:Fetus / Q000187:drug effects* / Q000502:physiology; D007700:Kinetics; D009994:Osmolar Concentration; D011247:Pregnancy; D012756:Sheep; D014556:Urine
D001127:Arginine Vasopressin; D003894:Deamino Arginine Vasopressin