PLASMA CORTISOL AND ADRENOCORTICOTROPHIC HORMONE IN NORMAL MEN AND NON-PREGNANT WOMEN, NORMAL PREGNANT WOMEN AND WOMEN WITH PRE-ECLAMPSIA

Summary

Determinations of plasma cortisol and adrenocorticotrophic hormone (ACTH) have been made in normal men and non-pregnant women, in normal pregnant women and women with pre-eclampsia, in maternal and cord blood during normal vaginal delivery and during delivery by Caesarean section. The findings in normal individuals, including the demonstration of diurnal variations, are in agreement with those of other workers, thus validating the methodology used. In pregnancy the plasma cortisol is raised and ACTH lowered so that, in comparison with non-pregnant individuals, the ACTH/cortisol ratio is greatly reduced. In pre-eclamptic pregnancies, on the other hand, the plasma cortisol tends to be lower and the ACTH much higher than in normal pregnancies, so that the ACTH/cortisol ratio is similar to that found in non-pregnant individuals. This rise in ACTH/cortisol ratio may occur in pregnant women before the development of oedema, proteinuria and hypertension. It appears that in pregnancy adrenocortical responsiveness to ACTH is enhanced while in pre-eclampsia the ability to secrete cortisol is relatively impaired, leading to increased ACTH secretion and this, by stimulating an increased output of aldosterone and possibly other salt-retaining steroids, may partly be responsible for the manifestations of pre-eclampsia. The concentration of cortisol in cord blood is lower than that in maternal blood at the time of delivery and both these concentrations are lower during delivery by Caesarean section than during normal vaginal delivery. On the other hand, although during delivery the ACTH levels in cord blood and maternal blood are greatly elevated, the difference between them is not significant, suggesting that the maternal adrenal cortex is more responsive to ACTH stimulation than the fetal adrenal cortex.