EFFECTS OF PROSTAGLANDIN E-2 ON RENAL-FUNCTION AND LUNG LIQUID DYNAMICS IN FETAL SHEEP

1, The aim of the present study was to determine the effects of prolon ged prostaglandin E-2 (PGE(2)) administration on the function of the f oetal kidneys and lungs in order to gain a greater understanding of th e role played by PGE(2) in the control of foetal fluid balance, By stu dying the effects of PGE(2) at two gestational ages, we have also been able to examine the influence of age. 2, We studied the effects of 26 h PGE(2) infusion on foetal sheep at a mean (+/-SEM) of 120.0 +/- 0.6 (n = 6) and 139.0 +/- 0.8 (n = 4) days of gestation. In both groups, foetal urine production was significantly inhibited throughout the inf usion period (P < 0.05), In younger, but not older foetuses, urine pro duction returned to control values within 24 h of ending the infusion (P < 0.05). This PGE(2)-induced anti-diuresis was associated with foet al hypoxaemia and acidaemia, a reduction in free water clearance and a n increase in foetal plasma arginine vasopressin concentrations (P < 0 .05). 3, During PGE(2) infusions, foetal breathing movements were inhi bited, the effect being greater and more sustained in older foetuses ( P < 0.05). 4, Infusions of PGE(2) led to increased lung liquid product ion at both ages (P < 0.05); lung liquid volumes were reduced in older foetuses (P < 0.05), but were unchanged in younger foetuses, The redu ction in lung liquid volume in older foetuses may have been due to inh ibition of foetal breathing. 5, We conclude that increased circulating levels of PGE(2) have profound effects on foetal renal and lung funct ion which, if sustained, could compromise foetal lung development and perinatal well-being.