PORPHYRINS IN PATHOLOGIC EXCRETA 



591 



in normal rat urine is unknown. Observation of the predominance of copro- 

 porphyrin III in the urine of these animals has therefore not the same sig- 

 nificance as it has in humans. 



Porphyrinuria is usually, but not always {28If2), accompanied by an 

 increased excretion of coproporphyrin in the feces; this is usually of type I 

 even when type III coproporphyrin is found in the urine, except in methyl 



TABLE II 



Excretion of Uroporphyrins in Diseases 



" Human urine unless specified. '' Porphyria may have also been present. " In 

 sensitive individuals. 



chloride poisoning, where the fecal coproporphyrin is also of type III (4-21). 

 Apparently the liver excretes coproporphyrin I more readily into the bile 

 than coproporphyrin III {2986). 



One may summarize these observations by stating that usually a 

 mixture of the two isomerides is excreted, with type I prevailing in 

 most diseases particularly in those in which blood pigment destruc- 

 tion is increased (Dobriner, Watson), type III prevailing only in 

 some toxic porphyrinurias.* The physiologic significance of these 

 observations will be discussed below. 



Porphyrias. Chronic congenital porphyria is a disease inherited as a 

 Mendelian recessive and characterized by the formation and excretion of 

 enormous amounts of uroporphyrin and coproporphyrin in the urine, deposi- 

 tion of uroporphyrin in the bones, and light sensitation of the skin. The 

 classic experiments of Garrod {982J818) were followed by those of 

 Giinther (1070,1071), Borst and Konigsdorffer {-322), H. Fischer, Schumm, 

 and many other investigators. Uroporphyrin was first isolated in the Petry 

 ease (see Sec. 3.2.^2.) by Fischer {779,781 J82,784,785,833,84o) and Schumm 

 {2506). In animals a disease of the same kind was first described as "ochro- 

 nosis." Poulsen {2182) and Schmey {2445) discovered porphyrin in affected 

 cattle, Tappeiner {2738) in pigs. Fink {764,767,772) and Fikentscher {7.5-5) 

 established the essential similarity of this animal disease to chronic congenital 



* Also in poliomyelitis (Watson and co-workers, .3004aa). 



