Chenodeoxycholic acid therapy in erythrohepatic protoporphyria.

The short-term effect of chenodeoxycholic acid administration on the excretion of protoporphyrin was investigated in 5 patients suffering from erythrohepatic protoporphyria. Faeces were collected for 7 days, 10 ml of bile was sampled daily and blood was drawn every 2 to 3 days. Chenodeoxycholic acid was given in a dosage of 15 mg/kg/day from the 8th day. Collection of faeces, bile and blood was then continued for 10 more days. Protoporphyrin concentration was measured by high-pressure liquid chromatography and fluorometry. Following the administration of chenodeoxycholic acid the concentration of protoporphyrin in faeces and bile decreased significantly. In addition, all patients showed a significant decrease in erythrocyte protoporphyrin concentration. These results indicate that chenodeoxycholic acid therapy causes a marked decrease in the excretion of protoporphyrin in patients with erythrohepatic protoporphyria. The subsequent decrease in erythrocyte protoporphyrin suggests that chenodeoxycholic acid inhibits the production of protoporphyrin in the liver.