The amount of uroporphyrin I (pmol x mg [protein.sup.-1] x [h.sup.-1]) formed was calculated as follows: 0.75 (conversion factor from copro- to uroporphyrin) x 1.527 (pmol/ng) x 3 (sample volume in mL) x the amount of coproporphyrin I measured ([micro]g/L):protein (mg).
Excretion of uroporphyrin is increased in AIP, similar to porphyria cutanea tarda, which is the commonest cutaneous porphyria accompanied by mild liver failure and photosensitivity but no acute attacks.
The results for these patients were normal or showed modest increases of uroporphyrin I and III and heptacarboxyl porphyrin (Table 1 and Fig.
We found a greater increase of plasma uroporphyrin I compared with uroporphyrin III in renal failure, similar to the reports of Seubert et al.
In the present three patients, the origin of the fecal uroporphyrin is
presumably from nonenzymatic condensation ofPBG.