Cyclooxygenase-2 (COX-2) is involved in kidney morphogenesis and is transiently elevated in the immature kidney. In adult rats, renal cortical COX-2 expression is tonically suppressed by mineralocorticoids (MC) and glucocorticoids (GC) and induced by chronic salt restriction. Young rats have low levels of GC and are in a state of relative volume depletion… (More)
Fig. 2. Renal COX-2 immunostaining in P14 rats. In control rat kidneys, intensive COX-2-ir was found in many epithelial cells of macula densae and cortical thick ascending limbs (A, arrows). B: although markedly decreased, COX-2-ir was still found in the cortex with maximal inhibition by salt supplementation. Cortical COX-2 expression decreased significantly after treatment with corticosterone (CS) or DOCA from P7 to P14. Fewer COX-2-ir cells were found in CS-treated (C) than DOCAtreated animals (D). Both the glucocorticoid receptor (GR) antagonist RU486 (E) and the mineralocorticoid receptor (MR) antagonist spironolactone (G) blocked CS inhibition of cortical COX-2 expression. DOCA suppression of cortical COX-2 expression was slightly blocked by RU486 (F) but was completely blocked by spironolactone (H). A-H: 700-nm-wide magnification.