Maternal undernutrition increases arterial blood pressure in the sheep fetus during late gestation

1. We have investigated the effect of a 50 % reduction in maternal nutrient intake during the last 30 days of pregnancy on arterial blood pressure and on arterial blood pressure responses to angiotensin II (AII) and the angio tensin converting enzyme (ACE) inhibitor captopril in the sheep fetus at 11 5-125 and at 135-145 days gestation (term = 147 +/- 3 days gestation). 2. Fetal plasma glucose concentrations were lower in the undernourished (UN ) group compared to the control animals. There was no difference, however, in fetal plasma cortisol or adrenocorticotrophic hormone (ACTH) concentrati ons between the UN and control groups between 115 and 145 days gestation. 3. During the first 10 days of undernutrition, maternal plasma concentratio ns of cortisol M ere increased in the UN group compared to controls. At 115 -125 days gestation, fetal arterial blood pressure was also higher in the U N group compared with controls and there was an inverse relationship (r = - 0.62, P < 0.05) between mean arterial pressure and the fetal plasma concent rations of ACTH in the UN group. Fetal blood pressure responses to increasi ng doses of angiotensin IT were also higher (P < 0.05) in UN compared to co ntrol animals at 115-125 days gestation. 4. Between 135 and 145 days gestation, fetal arterial blood pressure was in creased in UN fetal sheep and mean arterial blood pressure was correlated w ith fetal plasma concentrations of cortisol. 5. Increased arterial blood pressure and responsiveness to AII measured in the fetuses of nutrient-restricted ewes may be related in part to fetal exp osure to the actions of cortisol derived from transplacental transfer durin g the first 10 days after the start of the restricted feeding regime.