[Effect of dermatocorticoids on the activity of hepatic tryptophane pyrrolase in the guinea pig (author's transl)].

The enzyme activity of tryptophane pyrrolase in guinea pig liver can be measurably increased--as in other mammalian species--by systemic administration of corticoids, but this effect is short-lived and achieved only with high s.c. doses of, e.g., prednisolone (Ultracorten-H-hydrosoluble). In contradistinction and rather surprisingly the enzyme activity is variably but markedly reduced by high-dosed and protracted epicutaneous application (10 times within 2 weeks) of the well-known dermatocorticoids: hydrocortisone, fluocinolone acetonide, and clobetasol propionate. This reaction must be explained by the capacity of these corticoids to inhibit, after their percutaneous absorption, the functional axis pituitary--adrenal cortex--liver, the stimulatory role of which is mandatory for the endogenous basic activity of hepatic tryptophane pyrrolase.