The Effects of Chronic Hypoxia on Glucocorticoid Receptors in the Fetal Adrenal Medulla of the Sheep
Hypoxia is a serious condition in the developing fetus, potentially causing numerous and adverse health conditions during maturation. If exposed to chronic hypoxia over the entire course of gestation (long term hypoxia - LTH), the fetus has the capability to adjust to the adverse conditions, and this alteration is mediated by products of the adrenal gland, although the mechanism allowing this adjustment remains under study. Recent experiments have implied reduced local glucocorticoid hormone sensitivity in the adrenal medulla of LTH animals exposed to high altitudes, suggesting changes in one or more characteristics of the glucocorticoid receptor (GS) within this tissue. The aim of this study was to examine changes in these GR characteristics in LTH animals as compared to animals kept under normal oxygen conditions (normoxic animals). The experiments were performed in LTH and normoxic sheep fetuses, including western blotting with GR specific polyclonal antibodies to quantify GR in the adrenal medulla and immunohistochemical localization of the GR within the adrenal gland. The western blot results showed no significant variation in GR expression between normoxic and LTH animals in the medulla. The immunolocalization analysis indicated that GR was evenly distributed in the medullary tissue and did not differ between the two groups. In the cortex, however, GR had heightened localization in the zona fasciculate region in LTH animals as compared to normoxic controls. The reduced flucocorticoid sensitivity in the adrenal medulla of LTH fetuses will be further investigated.
Root, B. (2006). The Effects of Chronic Hypoxia on Glucocorticoid Receptors in the Fetal Adrenal Medulla of the Sheep (Undergraduate honors thesis, University of Redlands). Retrieved from http://inspire.redlands.edu/cas_honors/27
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