Serum gastrin concentrations in dogs with primary hyperparathyroidism.

BACKGROUND: Hypercalcemia has been associated with hypergastrinemia in humans. Hypergastrinemia could be responsible for gastrointestinal (GI) signs in dogs with primary hyperparathyroidism (PHPT). HYPOTHESIS/OBJECTIVES: (a) Determine whether hypergastrinemia occurs in dogs with PHPT, (b) assess for potential correlations among ionized calcium (iCa), parathyroid hormone (PTH), and serum gastrin concentrations, and (c) determine whether gastrin concentrations decrease after management of PHPT. ANIMALS: Phase 1: 151 client-owned dogs at the time of PHPT diagnosis, Phase 2: 24 dogs that underwent treatment for PHPT. METHODS: Dogs with azotemia, concurrent disease, or those receiving acid suppressants were excluded. Twenty-four treated dogs had baseline and repeat quantification of serum gastrin, PTH, and iCa concentrations 4 weeks after treatment. The effect of treatment on gastrin, iCa, and PTH concentrations was assessed using Wilcoxon signed rank sum tests. Fisher exact testing was used to compare the proportion of dogs with hypergastrinemia in dogs with and without GI signs. RESULTS: Twenty-seven of 151 PHPT dogs (17.9%) had increased pre-treatment serum gastrin concentrations (median, 45.0 ng/L; interquartile range [IQR], 20.0 ng/L). Gastrin concentrations were not correlated with iCa (P = .92) or PTH (P = .60). Treatment of PHPT decreased PTH (P < .001) and iCa concentrations (P < .001), but not gastrin concentrations (P = .15). The proportion of dogs with hypergastrinemia with and without GI signs did not differ (P = 1.00). CONCLUSIONS AND CLINICAL IMPORTANCE: Mild increases in serum gastrin concentrations may be seen in dogs with PHPT, but this finding is independent of the presence of GI signs.

Establishment of a reference interval for 12-hour fasted serum gastrin concentration in adult dogs.

BACKGROUND: Adherence to traditional 24-h fasting periods for serum gastrin concentration in dogs can be challenging and may delay the institution of therapies for suspected hypergastrinemia. Peer-reviewed publications regarding serum gastrin reference intervals (RI) are lacking. Hypercalcemia is associated with hypergastrinemia in people; limited data exist in dogs. OBJECTIVE: The objective of the study was to generate a RI for a 12-h fasted serum gastrin concentration in dogs and to investigate whether correlations exist with age, weight, sex, and total calcium concentration. METHODS: Fifty-five healthy adult dogs (>1 year of age). The screening included: medical history, physical examination, CBC (15 dogs), and serum chemistry (55 dogs). Gastrin was measured via a commercial radioimmunoassay. The RI for 12-h fasted serum gastrin concentration was calculated according to the recommendations of the American Society for Veterinary Clinical Pathology. Additionally, data were evaluated for correlation with selected variables. RESULTS: The RI for serum gastrin following a 12-h fasting period was 15.1-78.9 ng/L with 90% confidence intervals for the lower and upper limits of 14.0-22.9 and 68.3-83.0 ng/L, respectively. A generalized linear model did not detect significant relationships between gastrin and age (P = 0.48), sex (P = 0.30), weight (P = 0.93), or total calcium concentration (P = 0.84). CONCLUSIONS: A 12-h fasted serum gastrin concentration RI has been established. Given the limited range of serum calcium concentrations in our healthy study population, additional investigations are needed to determine the effects of hypercalcemia on serum gastrin concentrations in dogs and for any potential clinical consequences thereof.