POTENTIATION OF REDUCED UTEROPLACENTAL PERFUSION-PRESSURE HYPERTENSION IN PREGNANT RABBITS

Objective: We tested whether indomethacin (IND) potentiates the elevat ion of blood pressure induced by the reduction of the uteroplacental p erfusion pressure (RUPP). Methods: In pregnant rabbits on the 21 st da y of the 30-day gestation, the uteroplacental perfusion pressure was r educed by 68 +/- 5% using a clip placed on the abdominal aorta below t he renal arteries. IND suppositories (15 mg/kg each) were administered 1 and 2 days following surgery. Results: After the second dose, MAP o f IND-treated RUPP rabbits was higher (92 +/- 9 mm Hg, n = 10) than in those receiving placebo (78 +/- 12, n = 9, P < .01). MAP of sham-oper ated pregnant rabbits with or without IND was 61 +/- 9 and 58 +/- 8 mm Hg, respectively (NS). Placebo-treated RUPP animals evidenced an enha nced urinary sodium excretion as compared to normotensive control rabb its receiving placebo (3.27 +/- 0.69 mmol/kg/day vs. 1.49 +/- 0.74, P < .001). Enhanced urinary sodium excretion was blunted by IND in RUPP rabbits (1.25 +/- 0.37, P < .001). Conclusion: (1) IND potentiates the hypertensive response induced by RUPP. (2) the reduction of urinary s odium excretion may be one of the several pharmacological effects of I ND aggravating hypertension in this state.