EFFECT OF GLUCOCORTICOIDS AND MINERALOCORTICOIDS ON GENE-EXPRESSION OF ATRIAL-NATRIURETIC-PEPTIDE BY RAT ATRIA INVIVO

The effect of gluco- and mineralocorticoids on atrial natriuretic peptide (ANP) gene expression as well as plasma sodium and potassium concentrations was studied in both intact and adrenalectomized Wistar rats. Atria total RNA was extracted with cold phenol method and hybridized to alpha-P-32 labeled rat ANP-cDNA probe. The ANP gene transcripts in intact rats receiving dexamethasone and in adrenalectomized rats receiving both dexamethasone and deoxy-corticosterone increased by twofold, while there were no significant changes in the other groups. There were no parallel correlations between the rise of corticoid hormones-induced plasma Na+ concentration and the enhancement of rANP-mRNA level. The results suggest that glucocorticoids, when used together with mineralocorticoids, may directly increase ANP gene expression, whereas administration of mineralocorticoids alone has no effect on ANP gene expression.