Ascorbate status of patients with porphyria cutanea tarda symptomatica and its effect on porphyrin metabolism.

The ascorbate status and the effect of loading doses of ascorbic acid (1,5 g per day by mouth for 7 days) on the porphyric process were studied in 7 black men with porphyria cutanea tarda symptomatica. It was found that the ascorbate stores were depleted in these patients as judged by serum and leucocyte ascorbate levels. Temporary repletion of the ascorbate stores was effected by the loading doses of ascorbic acid: Serum iron concentrations increased in 6 patients; urinary iron excretion showed small peaks a few days after ascorbic acid therapy commenced; haemoglobin concentration was not affected; excessive amounts of oxalate were excreted in the urine; neither total urinary porphyrin excretion nor the composition of the urinary porphyrins was affected in a way which could be related to ascorbate therapy. Further evidence that ascorbate depletion is not important in the induction of porphyria was found when the ascorbate status of siderotic rats, rendered porphyric by hexachlorobenzene-feeding, was examined. Stores of ascorbate and the oxidative catabolism of ascorbate were not different in the prophyric rats as compared with normal litter mates.