URINE 467 



UROROSEIN 



This is a pigment which is not present in normal urine but may 

 be detected in the urine in various diseases, such as pulmonary tuber- 

 culosis, typhoid fever, nephritis, and stomach disorders. Urorosein, 

 in common with various other pigments, does not occur preformed in 

 the urine, but is present in the form of a chromogen, which is trans- 

 formed into the pigment upon treatment with a mineral acid. Herter 1 

 showed this chromogen to be indole acetic acid, 



H 



C C COOH 

 CH 



NH H 



Normal urine responds to the urorosein reaction (see below) if nitrites 

 are present. 



EXPERIMENTS 



1. Nitrite-Hydrochloric Acid Test (Urorosein Reaction). To 10 c.c. of urine 

 in a test-tube add 2 c.c. of concentrated hydrochloric acid and a few drops of a 

 i per cent solution of potassium nitrite. A rose-red color indicates urorosein. 



The chromogen (indole acetic acid) has been changed into urorosein 

 by oxidation. 



2. Robin's Reaction. Acidify 10 c.c. of urine with about 15 drops of con- 

 centrated hydrochloric acid. Upon allowing the acidified urine to stand, a rose-red 

 color will appear if urorosein is present. 



3. NencM and Sieber's Reaction. To 100 c.c. of urine in a beaker add 10 c.c. 

 of 25 per cent sulphuric acid. Allow the acidified urine to stand and note the ap- 

 pearance of a rose-red color. The pigment may be separated by extraction with 

 amyl alcohol. 



NEPHROROSEIN 



This pigment is closely related to urorosein 2 and like urorosein it is 

 produced from a chromogen when the urine is treated with nitric acid 

 or with concentrated hydrochloric acid and a little sodium nitrite 

 solution. It is sometimes called ^-urorosein to differentiate it from the 

 true urorosein which is termed a-urorosein. Nephrorosein occurs only 

 in pathological urines. 



DROCHROMOGEN 



This is the chromogen of urochrome, the normal urinary pigment 

 (see Chapter XXII) . It is claimed that the urochromogen reaction of the 



1 Herter: Jour. Biol. Chem., 4, 253, 1908. 

 3 Arnold: Zeit. physioL Chem., 71. 



