Experiments were conducted in intact and adrenalectomized female Wistar rats given dexamethasone, deoxycorticosterone or both, and atria total RNA was extracted with cold phenol method and hybridized to rat ANP-cDNA probe labeled with alpha-32P. The ANP gene transcripts in intact rats receiving dexamethasone and in adrenalectomized rats receiving dexamethasone and deoxycorticosterone increased by 2-fold, while there were no significant changes in the other groups. The results suggest that glucocorticoids enhance ANP gene expression, an effect relying on the presence of mineralocorticoids which given alone does not give rise to ANP gene expression enhancement.