Acute effects of maternal stress on fetal blood catecholamines and hypothalamic LH-RH content.

The acute effects of maternal stress (restraint for 20 to 140 min) on the plasma levels of epinephrine, norepinephrine and dopamine in pregnant rats and their fetuses as well as on the catecholamine content of fetal adrenals and the LH-RH content of fetal hypothalami, were investigated at day 22 of gestation. Despite of a relatively moderate increase of maternal plasma catecholamines a significant increase of norepinephrine (p less than 0.05) and dopamine (p less than 0.05) levels in plasma of the fetuses 30 min after starting maternal stress was observed. The fetal blood concentrations of catecholamines before and during maternal stress were significantly higher than those of the mothers (p less than 0.05 to p less than 0.001). A gradual decrease of the fetal adrenal content of epinephrine and norepinephrine was found, whereas an unchanged content of dopamine of fetal adrenals was registered during maternal restraining. The LH-RH content of fetal hypothalami rose significantly (p less than 0.005) 60 min after starting maternal stress and returned to initial values 140 min after starting restraining.