Is the fetal lung a mineralocorticoid receptor target organ? Induction of cortisol-regulated genes in the ovine fetal lung, kidney and small intestine.
Bottom Line: Expression of corticosteroid-induced genes in renal cortex increases at term; in small intestine the induction occurs postnatally.In contrast, in lung expression of MR and GR mRNAs were greater at 100 days to term than postnatally and 11 beta-HSD1 peaked at 145 days; the corticosteroid-induced genes also increased prenatally: Sgk-1 and ENaC alpha increased by 120 days, peaking at 145 days, and Na,K-ATPase alpha1 was greatest at 130 days.The expression of high levels of MR and 11 beta-HSD1 in preterm fetal lung suggest low endogenous fetal cortisol may exert actions at the high affinity MR in vivo, leading to increases in expression of sodium channels important in the regulation of lung liquid secretion and reabsorption.
Affiliation: Department of Pharmacodynamics, University of Florida, Gainesville, FL 32610, USA. email@example.comShow MeSH
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Mentions: GR was abundantly expressed in lungs, and renal cortex and medulla. Mean GR mRNA expression relative to 18S was approximately 8-fold greater in lung than in renal cortex, and almost 20-fold greater than in small intestine at 130 days’ gestation, however expression at postnatal day 7 was more similar among tissues (table 1). GR expression in the lung was significantly increased during the second half of fetal life and was significantly higher in fetal lung than in postnatal lung (fig. 1a). In renal cortex, GR expression increased by day 145, but decreased postnatally (fig. 2a). GR mRNA expression was not significantly different across gestational age in small intestine or renal medulla (fig. 3a, 4a). In contrast, GR expression in small intestine was significantly increased at postnatal day 7 (fig. 4a).
Affiliation: Department of Pharmacodynamics, University of Florida, Gainesville, FL 32610, USA. firstname.lastname@example.org