Abstract
Summary
Adult female rats received 30 mg/kg morphine sulfate (MS) ip 2 hr after sc injection of various doses of dexamethasone (Dex) or saline. Plasma corticosterone levels were markedly elevated 2 hr after MS and such elevation was partially suppressed by pretreatment with 20 μg/kg Dex and markedly inhibited by 100 μg/kg of this steroid; 5 μg/kg failed to cause significant suppression of plasma corticosterone levels. Despite treatment with Dex and MS, all groups showed significant corticosterone responses to 3-min ether stress. Because of the relatively low doses used, Dex appears to be a potent inhibitor of the ACTH-releasing action of MS.
The excellent technical assistance of Jessie Kroning and Lucile Perkins is gratefully acknowledged.
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