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 angiotensin converting enzyme (ACE) inhibitor captopril in the sheep fetus at 115-125 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) concentrations between the UN and control groups between 115 and 145 days gestation. 3. During the first 10 days of undernutrition, maternal plasma concentrations of cortisol were increased in the UN group compared to controls. At 115-125 days gestation, fetal arterial blood pressure was also higher in the UN group compared with controls and there was an inverse relationship (r = -0.62, P < 0.05) between mean arterial pressure and the fetal plasma concentrations of ACTH in the UN group. Fetal blood pressure responses to increasing doses of angiotensin II were also higher (P < 0.05) in UN compared to control animals at 115-125 days gestation. 4. Between 135 and 145 days gestation, fetal arterial blood pressure was increased in UN fetal sheep and mean arterial blood pressure was correlated with 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 exposure to the actions of cortisol derived from transplacental transfer during the first 10 days after the start of the restricted feeding regime.