[The influence of ursodesoxycholic acid (URSO) on griseofulvin (GF)-induced protoporphyria]

To investigate the influence of ursodesoxycholic acid (URSO) on griseofulvin (GF)-induced protoporphyria mice, analysis of hepatic, erythrocytic, and fecal porphyrin levels and histopathological examinations were performed in dd-Y strain mice treated with 0.5% GF and/or 0.5% URSO. We observed no difference of hepatic and fecal porphyrin levels between the GF group and GF with URSO group, although an elevation of erythrocytic porphyrin levels was seen in the GF with URSO group. However, remarkable hepatic atrophy revealed in the GF with URSO group. Furthermore, a strong emission of red fluorescence was observed in the liver under long wave ultraviolet. Histopathologically, many focal necrosis was found in the liver specimen treated with GF and URSO. We expected that URSO might facilitate the excretion of porphyrin from bile to feces because of suppression of transfer from serum to erythrocyte like cholic acid (CA). But, the action of URSO appears to be different from that of CA. We consider that the 0.5% concentration of URSO plays a role in the cytotoxic effect to the liver.