Opposite effects of dexamethasone and ACTH on the adrenal cortex response to ethane dimethanesulphonate (EDS)

Recently we have reported that ethane dimethanesulphonate (EDS), the Leydig cell cytotoxin, caused marked atrophy of the adrenal cortex of adult male rats. The aim of this work was to examine whether a 9-day treatment with de xamethasone (0.25 mg/kg/d) or ACTH (40 IU/kg/d), which started 4 days prior to administration of a single dose of EDS (75 mg/kg), influenced the respo nse of the inner adrenocortical zones to the toxin. On day 15 after adminis tration of EDS, adrenal weight was significantly decreased in saline treate d rats, but glandular and serum corticosterone levels were not altered. In dexamethasone-suppressed rats, the effect of EDS was augmented; an addition al decrease in adrenal weight was accompanied by reduced adrenal and serum corticosterone levels. In ACTH-treated animals EDS was ineffective. These r esults demonstrate that the deleterious effects: of EDS on rat adrenal cort ex can be prevented by ACTH and potentiated by dexamethasone.