Continuous infusion of cortisol into adrenalectomized fetal sheep during the last 72 h of gestation (term = 145 +/- 2 days) produced a significant (P < 0.05) rise in fetal serum tri-iodothyronine (T3) mean +/- S.E.M. concentrations from 398 +/- 65 to 1340 +/- 238 ng/l. A concurrent decrease in plasma thyroxine (T4) levels was observed in three out of four animals. No significant changes in the concentrations of either hormone were noted prior to the start of cortisol infusion. The plasma concentrations of cortisol, T3 and T4 at term were similar to those in untreated full-term lambs. Adrenalectomized fetuses not given cortisol infusions still had low levels of T3 at term, with no increase being observed. The results suggest that cortisol plays an important role in the increase of fetal plasma T3 observed towards the end of gestation. This is probably achieved by the stimulation of the monodeiodination of T4 to T3 in the peripheral tissues.

No abstract

No abstract

Pre-eclampsia leads to disturbed fetal organ development, including metabolic syndrome, attributed to altered pituitary-adrenal feedback loop. We measured cortisol metabolites in infants born from pre-eclamptic and normotensive women and hypothesised that glucocorticoid exposure would be exaggerated in the former. Twenty-four hour urine was collected from infants at months 3 and 12. Cortisol metabolites and apparent enzyme activities were analysed by gas chromatography-mass spectrometry. From 3 to 12 months, excretion of THS, THF and pregnandiol had risen in both groups; THF also rose in the pre-eclamptic group. No difference was observed with respect to timing of the visit or to hypertensive status for THE or total F metabolites (P>0.05). All apparent enzymes activities, except 17α-hydroxylase, were lower in infants at 12 compared to 3 months in the normotensive group. In the pre-eclamptic group, only 11β-HSD activities were lower at 12 months.17α-hydroxylase and 11β-HSD activities of tetrahydro metabolites were higher in the pre-eclamptic group at 3 months (P<0.05). 11β-hydroxylase activity increased in the pre-eclamptic group at 12 months. Cortisol excretion, determined by increased 11β-hydroxylase, compensates for high 11β-HSD-dependent cortisol degradation at 3 months and at 12 months counterbalances the reduced cortisol substrate availability in infants born from pre-eclamptic mothers.