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

IV. Assessment of Adrenocortical Function
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TABLE 19-2 Basal Corticosteroid Concentrations in Healthy Animals
Hormone (Unit) Species (n) Fluid Sampling Time Mean SD (Range) Reference
Cortisol Dog (14) Plasma After overnight fast 46.0 1.3 ( Beerda et al ., 1996 )
(nmol/l) Saliva After overnight fast 4.7 0.4 ( Beerda et al ., 1996 )
Cat (130) Plasma After overnight fast 79 79 (Javadi et al. , 2004)
Horse (7) Plasma 06.00h 251 115 (van der Kolk et al ., 2001 )
Saliva 06.00h 3.2 1.9 ( van der Kolk et al ., 2001 )
Plasma 18.00h 142.0 52.9 ( van der Kolk et al ., 2001 )
Saliva 18.00h 2.1 1.4 ( van der Kolk et al ., 2001 )
Cattle (39) Plasma 08.00–14.00 17.1 1.1 ( Beerda et al ., 2004 )
Cattle Milk Morning 1.24 0.13 ( Gygax et al ., 2006 )
Pig (6) Plasma — (27–355) ( Cook et al ., 1997 )
Saliva — (3.1–21.3) ( Cook et al ., 1997 )
Sheep (4) Plasma — 19.0 4.9 ( Turner et al ., 2002 )
Ferret (29) Plasma — (3–27) ( Schoemaker et al ., 2003 )
Aldosterone Dog (12) Plasma After overnight fast 118 14 ( Javadi et al. , 2003 )
(pmol/l) Cat (130) Plasma After overnight fast 267 135 ( Javadi et al ., 2004 )
Horse (6) Plasma — 63.0 12.8 ( McKeever and Malinowski, 1999 )
PRA Dog (12) Plasma After overnight fast 201 25 ( Javadi et al ., 2003 )
(fmol/l/s) Cat (130) Plasma After overnight fast 240 165 ( Javadi et al ., 2004 )
TABLE 19-3 Molar Urinary Corticoid Creatinine Ratios
Species (n) Season Range (Mean SD) Reference
Dog (28) 1.2–6.9 10 6 ( Stolp et al ., 1983 )
Dog (12) (9 4 10 6 ) ( Jones et al ., 1990 )
Dog (20) 0.5–17.7 10 6 ( Feldman and Mack, 1992 )
Dog (31) 0.1–31.2 10 6 ( Smiley and Peterson, 1993 )
Cat (42) 2–36 10 6 ( Goossens et al ., 1995 )
Ferret—intact Breeding (6.0 0.5 10 6 ) ( Schoemaker et al ., 2004 )
Ferret—intact Nonbreeding (1.5 0.2 10 6 ) ( Schoemaker et al ., 2004 )
Ferret—castrated Nonbreeding (1.3 0.1 10 6 ) ( Schoemaker et al ., 2004 )
Meanwhile, for the dog, Stolp et al . (1983) have introduced
another measurement reflecting cortisol secretion
over a period of time. In this approach, the 24-hour urine
collection has been replaced by morning samples. The urinary
corticoids (largely cortisol) are measured by radioimmunoassay
and related to the creatinine concentration. In an
assessment ( Rijnberk et al ., 1988 ), the corticoid/creatinine
ratios were found to have a higher diagnostic accuracy in
the diagnosis of hyperadrenocorticism than the commonly
used dexamethasone screening test (see Section IV.C.3).
The method has also been introduced for diagnostic
use in the cat ( de Lange et al ., 2004 ; Goossens et al .,
1995 ) and the ferret ( Gould et al ., 1995 ; Schoemaker
et al ., 2004 ). Also for these species the determination of
the urinary corticoid/creatinine ratio appears to be valuable
for the diagnosis of hyperadrenocorticism.
4 . Salivary Cortisol
In saliva, the “ free ” (biologically active) fraction rather than
the “ total ” cortisol is measured. So far in animals, salivary
collection devices have been used primarily for research
purposes. In the past, a disadvantage has been the anesthesia
involved, although it does not inhibit salivary flow ( Phillips
et al ., 1983 ). In recent years there has been renewed interest
in the approach, especially now that a technique has been
introduced for saliva collection in unrestrained animals.
Cortisol measurements in saliva may serve as a noninvasive
indicator of stress in animals. By allowing the animals to
chew on large wads of cotton for up to 30sec, adequate saliva
samples can be obtained from dogs ( Vincent and Michell,
1992 ). The same method has been used successfully in
pigs ( Parrott and Misson, 1989 ) and sheep ( Cooper et al .,