The
N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-
PABA):
xylose test was evaluated in 5 clinically normal dogs, 5 dogs with pancreatic exocrine insufficiency (PEI), and 7 dogs with intestinal malabsorption. A
solution of BT-
PABA (1 g/100 ml) and
d-xylose (10 g/100 ml) was given orally (5 ml/kg of
body weight) to dogs in each group. Plasma
p-aminobenzoic acid (
PABA) curves were decreased in dogs with PEI and intestinal malabsorption (P < 0.05) but were the lowest in dogs with PEI, compared with clinically normal dogs.
Xylose values in dogs with malabsorption were decreased (P < 0.05), compared with clinically normal dogs. Dogs with PEI had plasma
xylose values that were intermediate to values in clinically normal dogs and dogs with intestinal malabsorption. Results of BT-
PABA:
xylose testing were compared with results of
sodium PABA:
xylose testing, to determine whether decreased
PABA values obtained by the BT-
PABA:
xylose test were caused by free
PABA malabsorption or by maldigestion of BT-
PABA. The
sodium PABA:
xylose test was performed in dogs from each group by
oral administration of a
solution (5 ml/kg) of
sodium PABA (0.372 g/100 ml) and
d-xylose (10.0 g/100 ml). Plasma
PABA values obtained by the
sodium PABA:
xylose test were similar in each group. Thus, different
PABA values obtained by the BT-
PABA:
xylose test were not caused by
PABA malabsorption.
Xylose values were similar to values obtained by the BT-
PABA:
xylose test. It was concluded that: (1) the BT-
PABA:
xylose test is a practical test for detecting maldigestion or malabsorption in the dog; (2) dogs with intestinal malabsorption may have functional PEI; and (3) decreased
PABA plasma values obtained by BT-
PABA:
xylose testing are not caused by malabsorption of free
PABA.