[Influence of p-amino-benzoic acid on the hexachlorobenzene induced porphyria in the rat (author's transl)].

The effect of p-amino-benzoic (PAB) acid on the experimental hexachlorobenzene (HCB) induced hepatic porphyria of female Wistar rats was determined under different conditions: Neither a simultaneous HCB-PAB application (prophylactic administration) nor the PAB application after manifestation of the HCB-porphyria (therapeutic administration) influenced significantly the excretin of urinary porphyrins or precursors (porphobilinogen or 5-amino-levulinic acid). PAB application decreased the cytochrome P-450 content in the liver of the rats whereas HCB incuded enzymatic activity of this monooxygenase measured by the O-dealkylation of 7-ethoxycoumarin was not diminished by PAB application. The glycine concentration and the glycine content of rat livers were not decreased by the simultaneous HCB-PAB treatment in contrast to PAB controls. These findings are discussed and the conclusion is drawn that there might be different types of human porphyria cutanea tarda. The predominently exogenously induced PCT in men and the HCB induced porphyria in rats cannot be influenced by PAB application.