Adrenal steroids and cardiac fibrosis.

Uninephrectomized rats maintained on 0.9% NaCl as drinking fluid and infused for 8 weeks with aldosterone 0.75 micrograms/h via subcutaneous osmotic minipumps respond with hypertension, cardiac hypertrophy, and both interstitial and perivascular cardiac fibrosis. Similar animals injected with desoxycorticosterone (20 mg/week), or the glucocorticoid antagonist RU 486 (2 mg/day) show interstitial cardiac fibrosis to a lesser degree than animals injected with aldosterone, and show perivascular fibrosis to a greater degree. These findings suggest that glucocorticoid antagonist activity may play a role in exacerbating perivascular collagen deposition in response to chronic mineralocorticoid and salt imbalance.