Hypoxic effects on the expression of mineralocorticoid and glucocorticoid receptors in human renal cortex epithelial cells

The effects of both mild and severe hypoxic conditions on the expression of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the primary human renal cortex epithelial cells (RCEC) were investigated. Slot blot analyses were performed with human β-actin cDNA and the cDNA probes for unique regions of MR and GR. The steady-state mRNA level of the house-keeping β-actin gene remains the same in RCEC under either normoxic or hypoxic conditions. However, there was a 45% reduction in MR expression and a 30% increase in GR expression, under mild hypoxic condition (15% O₂,) over 3 days. Furthermore, cells subjected to a severe hypoxic condition (0.5% O₂,) for 24 hours exerted a 22% reduction in MR expression and a 64% increase in GR expression. Changes in MR and GR expression may, in part, explain the physiological changes in adrenal cortical function observed in hypoxic conditions.