[A comparative analysis of corticosterone, cortisol and dexametasone effects on gastric erosion in rats]

We previously demonstrated that manifestation of gastroprotective or proulcerogenic effects of single dexamethasone injection depends on duration of the hormonal action before ulcerogenic stimulus, but not on the hormonal dose. In the present study we investigated dose and time dependence of corticosterone and cortisol effects on the gastric erosion in rats in comparative aspect with dexamethasone effects. Gastric erosion was induced by indomethacin (35 mg/kg, sc) in preliminary fasted rats. Single injection of corticosterone or cortisol at the doses of 25, 50, 100 mg/kg one hour before indomethacin administration resulted in dose dependent gastroprotective effects similar to dexamethasone effects. However, after extending the hormonal action till 24 h (before indomethacin administration), the gastroprotective effect of corticosterone (100 mg/kg) and cortisol (50 mg/kg) didn't transform into a proulcerogenic one, in contrast to dexamethasone, but simply disappeared. The absence of long-lasting corticosterone deficiency in blood after corticosterone and cortisol injection, which was observed after dexamethasone injection, could be at least one of the possible reasons for the absence of transformation of the gastroprotective action of corticosterone and cortisol to a proulcerogenic one.