The Possible Role of Prostaglandins in the System in the Newborn Hyperfunction of the Renin‐angiotensin‐aldosterone

Abstract

Plasma renin activity and plasma aldosterone concentration were measured by radioimmunoassay in eight newborn infants born vaginally to mothers on indomethacin treatment. Measurements were made in venous cord blood at birth and on the sixth day of life. The results were compared to those obtained in eight healthy control newborn infants of similar gestational age and birth weight. Maternal treatment with indomethacin was associated with a decrease of plasma renin activity (mean+SD) from 16.71 k2.76 ng/ml/hour in the control group to 9 a60 & 3.84 ng/ml/hour in the treated group. Plasma aldosterone concentration was lower in the cord blood of the treated group and a similar trend was demonstrated in the sixth day samples. It is suggested that the increased endogenous prostaglandin production during labour may be one of the factors responsible for the development of hyperactivity of renin-angiotensin-aldosterone system in the newborn.

Renin and angiotensin converting enzyme concentrations in the fetal and neonatal guinea‐pig.

“…Increased renal sympathetic activity at birth could stimulate renin secretion but, since high PRC are also measured in rats and rabbits which lack a fully functional sympathetic nervous system at birth (De-Champlain, Malmfors, Olson & Sachs, 1970), additional mechanisms are probably involved. Sulyok, Nemeth, Tenyi, Csaba, Thurzo & Hadnagy (1979) found that PRC of babies born to indomethacintreated mothers were lower than PRC of untreated newborns suggesting that endogenous prostaglandin production during labour might stimulate renin release in the newborn. The possibility that a lack of angiotensin II feedback at birth might contribute to the increase in PRC in the newborn guinea-pig is unlikely, since…”

The influence of the mode of delivery on the umbilical cord serum aldosterone levels in preterm newborn infants

“…A comparação entre as crianças nascidas de parto vaginal, nascidas de parto cesariano com trabalho de parto e de parto cesariano sem trabalho de parto mostrou que não houve diferença significativa em todas as variáveis estudadas, exceto no uso de anti-hipertensivos que foi significativamente maior nas mães submetidas a parto cesariano sem trabalho de parto do que nas mães que tiveram parto vaginal e nas que tiveram parto cesariano com trabalho de parto. A aldosterona não passa a barreira placentária e, portanto, os níveis séricos encontrados no sangue de cordão umbilical são de origem fetal 1,3,[15][16][17][18] .…”