Porphyrinogens in Urine in Various Types of Porphyrias

Abstract
Porphyrinogens were determined in very fresh, diluted morning urine from patients with 2 types of hepatic porphyria, using a simple and quick spectrophotometric method. Acidification by itself was insufficient for the complete conversion of colorless porphyrinogens into porphyrins in photometric determination of porphyrins in diluted urine. A correlation was shown between percent content of porphyrinogens and the sum of pentacarboxyporphyrin and coproporphyrin. A difference was found between the excretion of porphyrinogens in morning fresh urine in porphyria cutanea tarda (average porphyrinogen fraction 22.5%, SD 10.3% of total porphyrins) and in acute intermittent porphyria (average porphyrinogen fraction 77.1%, SD 9.3% of total porphyrins). The method is also suitable for the detection of urobilinoids in urine. Oxidation of the urine in acute intermittent porphyria is recommended before adsorption on talc and subsequent TLC, because porphyrinogens are not adsorbed on talc.