Abstract
We hypothesized that in the late-gestation sheep fetus there is an interaction between the prepartum rise in cortisol and the increase in placental estradiol production that allows expression of key components of the fetal hypothalamic-pituitary-adrenal (HPA) axis. Therefore, the goal of this study was to investigate the effects of cortisol on the fetal HPA axis in the presence and absence of increased placental estradiol production. We obtained fetal plasma samples and pituitary tissue from animals that had received an infusion of either cortisol, cortisol and 4-hydroxyandrostenedione (40HA, an aromatase inhibitor), saline, or saline + 40HA controls. Cortisol significantly decreased plasma adrenocorticotropic hormone concentrations, and in the presence of 40HA reduced pituitary proopiomelanocortin (POMC) mRNA levels in the pars distalis. There was no effect of any treatment on the expression of the key POMC processing enzymes, prohormone convertase-1 or -2 in the fetal pituitary. Conversely, levels of glucocorticoid receptor (GR) mRNA in the pituitary were increased with cortisol treatment in the absence of increased estradiol. We suggest that in the late-gestation sheep fetus, cortisol and estradiol have opposite effects on pituitary POMC and GR mRNA expression, and interact to regulate these key components of the fetal HPA axis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.