[Influence of theophylline on hexachlorobenzene induced porphyria (author's transl)]

Administration of 0.05% hexachlorobenzene (HCB) contained in the food to female (Wistar rats over a period of 60 days induced porphyria as measured by the increased urinary porphyrin excretion. One group of the rats was additionally treated with theophylline (150 mg/kg b.w./d). The concomitant theophylline application to rats with HCB induced porphyria increased their urinary excretion of porphyrin (p less than 0,1%) and its precursors (porphobilinogen and delta-aminolevulinic acid) in comparison to the HCB controls. The HCB induced increase of the hepatic cytochrome P-450 content was prevented whereas 7-ethoxycoumarine-deethylase activity was depressed concomitantly by theophylline. p-Nitro-anisole-demethylase activity was not influenced by this treatment. It is assumed that the delta-amino-levulinic acid synthase is induced by theophylline. The different behaviour of the porphyrin excretion and the cytochrome P-450 induction during this treatment leads to the conclusion that there is no direct or causal relationship between these two biochemical processes.