Effect of various antiinflammatory drugs on plasma acth and cortisol levels in rats

Abstract

Various antiinflammatory drugs have been injected i.p. to rais at doses equivalent to the maximal doses used in humans and plasma ACTH levels have been measured by a radio-bioassay. After acetylsalicylic acid, diclofenac and ibuprofen administration, a drop in plasma ACTH levels is observed, without a concomitant change in plasma cortisol levels. Small decrease in plasma ACTH is observed with ketoprofen, pirprofen and oxyphenbutazone; no change or a small increase is seen after azapropazone, naproxen, phenylbutazone and benzydamine. Repeated administration (five times 10 mg/kg every 24 hours) of acetylsalicyclic acid brings about a steady decrease of ACTH, which resumes its value after 48 hours. No change in cortisol levels are seen concomitantly to the short term drop in ACTH levels and small changes are seen in repeated administration of acetylsalicylic acid.