Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

IV. Porphyrias
249
i . Urine It is known that porphyrin excretion varies over
wide limits. Jorgensen (1961) in 52 cases found values for
urinary uroporphyrins between 6.3 to 3900 μ g/dl (0.076
to 46.96 μ mol/l) and coproporphyrins between 2.1 and
8300 μ g/dl (0.032 to 126.74 μ mol/l). At concentrations of
100 μ g/dl (1.53 μ mol/l) or more, a reddish discoloration
is discernible in the urine. At 1000 μ g/dl (15.27 μ mol/l) or
more, an intense red fluorescence of the urine is readily
observed when examined in the dark with Woods light.
The principal porphyrins excreted are URO I and COPRO
I and only a small fraction is of the type III isomers. The
percentage of each appearing in the urine is also variable.
There is usually a greater excretion of URO I than COPRO
I, but Jorgensen (1961) observed a greater excretion of
COPRO I than URO I.
Porphobilinogen is not usually found in bovine CEP
urine, and earlier reports of its presence ( Jorgensen and
With, 1955 ) have not been confirmed ( Jorgensen, 1961 ).
Normally colored, nonfluorescent urine of a CEP cow has
consistently given a definite pink Ehrlich reaction, but
unlike porphobilinogen aldehyde, the pigment is soluble in
chloroform. The nature of the pigment is unknown. Upon
heating on a steam bath for an hour or standing at room temperature
for several days, a red fluorescence is apparent on
exposure to UV light. Quantitative porphyrin determinations
of this urine yielded values of 135 μg/dl (1.63μmol/l) and
87 μg/dl (1.33μ mol/l) for uroporphyrin and coproporphyrin,
respectively. Watson et al. (1959) also described a similar
experience with bovine CEP urine.
ii . Bile and Feces Bovine fecal porphyrins may be derived
from two sources: the bile and from chlorophyll of the food.
The porphyrins derived from chlorophyll are excluded by
the usual analytical method. Essentially, the only porphyrin
found in the bile and feces of CEP cattle is COPRO I, and its
concentration varies over wide limits ( Tables 8-4 and 8-5 ).
Fecal coproporphyrin varied between 1.9 and 11,800 μg/g
(0.003 to 18.0 μ mol/g) and biliary coproporphyrin between
320 and 13,600 μg/dl (4.88–207.67μmol/l) (Jorgensen, 1961 ) .
Only small amounts of COPRO III have been observed in
feces. Watson et al. (1959) also observed this preponderance
of COPRO I in feces and also reported the presence of small
amounts of URO I.
iii . Plasma and Erythrocytes Only traces of free porphyrins
are normally present in the plasma and in the erythrocytes.
In bovine CEP plasma, Watson et al. (1959) observed
variable amounts of porphyrins that were in general equally
URO I (1 to 27 μg/dl; 0.012-0.33μ mol/l) and COPRO I (4.2
to 25 μ g/dl; 0.064 to 0.38 μ mol/l). A striking difference
as compared to the human disease was the high level of
free protoporphyrin in the erythrocytes of the CEP cow.
The significance of this high level of protoporphyrin was
unclear but was most likely related to the severe hemolytic
TABLE 8-5 Porphyrins in Blood and Excreta of Normal, Porphyric, and Porphyria Carrier Cattle a
Erythrocytes Plasma Urine Feces
Animals c COPRO b PROTO COPRO PROTO COPRO URO COPRO PROTO
Normal Mature Cows (N 10)
Trace Trace Trace Trace 2.05–6.15 0.80–1.60 111–428 15–125
(4.06) (1.09) (312 96) (75 30)
Mature Porphyric Cows
1184 3.0 61 15.3 1.8 410 378 5670 46
652 (N 3) 3.4 64 4.5 1.6 313 336 1900 12
2026 (N 2) 3.1 457 8.9 1.5 498 487 2090 62
718 89.7 36 1450 1280
Mature Porphyria Carrier Cows
1140 Trace Trace Trace Trace Trace Trace 292 88
1141 Trace Trace Trace Trace Trace Trace 273 92
Porphyric Calves, 2 to 6 Months Old
1857 (N 3) 2.9 109 1.5 Trace 13 70 796 144
1801 (N 3) 7.8 104 38.4 2.6 1430 1144 12 72
1959 18.6 288 Trace Trace 480 265 22 99
Porphyria Carrier Calf, 5 Months Old
1802 Trace Trace Trace Trace Trace Trace 495 40
a
Values are means given in micrograms per deciliter or micrograms per 100 g; values in parentheses are means plus or minus a single standard deviation ( Kaneko and Mills, 1970 ).
b
Abbreviations: COPRO, coproporphyrins; PROTO, protoporphyrins; URO, uroporphyrins.
c
N denotes number of animals or number of determinations per animal.