Effect of halopredone acetate on rat liver tryptophan oxygenase and tyrosine aminotransferase activities.

The possible inductive effect of a new local antiinflammatory steroid, 17,21-bis(acetyloxy)-2-bromo-6beta,9-difluoro-11beta-hydroxypregna-1,4-diene-3,20-dione (halopredone acetate; Topicon), on the rat liver enzymes tryptophan oxygenase and tyrosine aminotransferase was evaluated. The new steroid, when present in the implanted cotton-pellets or when s.c. injected, unlike the reference compound, fluocinolone acetonide, which induced a large increase in both enzymes, did not modify either tryptophan oxygenase or tyrosine aminotransferase. The results confirm that halopredone acetate elicits potent local antiinflammatory activity in the absence of systemic effects.