To measure serum fibroblast growth factor-19 (FGF-19) concentration and gallbladder volume in healthy dogs before and after feeding to determine whether serum FGF-19 concentration increases following gallbladder contraction and to assess FGF-19 stability in blood samples kept under different storage conditions after collection in tubes containing no anticoagulant or in serum separator tubes.
10 healthy dogs of various ages and breeds (30 blood samples and 30 gall-bladder volume measurements).
Serum FGF-19 concentration was measured with a commercially available ELISA. Gallbladder volume was determined ultrasonographically. Blood samples and gallbladder measurements were obtained from the dogs after food had been withheld for 12 hours (baseline) and at 1 and 3 hours after feeding. The stability of serum FGF-19 was assessed in samples collected in tubes containing no anticoagulant or in serum separator tubes and stored at –80°C for variable intervals or 4°C for 1 or 5 days.
Serum FGF-19 concentration was significantly increased from baseline at 1 and 3 hours after feeding. There was a significant decrease in gallbladder volume 1 hour after feeding, compared with baseline findings. Regardless of collection tube used, concentrations of FGF-19 in serum obtained from blood samples that were collected and immediately stored at –80°C differed significantly from concentrations in serum obtained from blood samples that had been collected and stored at 4°C for 5 days.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that postprandial gallbladder contraction results in increases of serum FGF-19 concentration in healthy dogs. Assessment of circulating FGF-19 concentration could be used to detect disruptions in the enterohepatic-biliary axis in dogs.