Objectives: The aim of this study was to evaluate the safety and efficacy of cabergoline to control hypersomatotropism (HST) and diabetes mellitus (DM) in cats.
Methods: This was a prospective cohort study. Twenty-three cats with HST and concurrent DM were enrolled. Cats received a dose of 10 μg/kg cabergoline q48h PO for 6 months. Serum insulin-like growth factor 1 (IGF-1) and fructosamine concentrations, insulin dose and Insulin Resistance Index (IRI) were measured at the time of diagnosis of HST and at the start of cabergoline treatment (t0), and 3 months (t1) and 6 months (t2) during cabergoline treatment.
Results: A decrease and normalization of serum IGF-1 concentration was observed in 35% and 26% of cats, respectively. Median IGF-1 (t0: 1350 ng/ml [range 832-1501]; t1: 1284 ng/ml [range 365-1501]; t2: 1240 ng/ml [range 263-1501]; P = 0.016) decreased significantly. Twelve cats underwent diagnostic imaging of the pituitary area. The median pituitary height at t0 of cats that experienced an IGF-1 reduction (n = 5/12) was significantly lower compared with those that did not experience an IGF-1 reduction (n = 7/12) (3.2 mm [range 3.1-3.7] vs 6 mm [range 3.5-9.5]; P = 0.011). Median fructosamine (t0: 628 µmol/l [range 400-963]; t1: 404 µmol/l [range 249-780]; t2: 400 µmol/l [range 260-815]; P <0.0001), insulin dose (t0: 1.3 IU/kg [range 0.5-4.6]; t0: 0.5 IU/kg [range 0-2.3]; t2: 0.4 IU/kg [range 0-2.1]; P <0.0001) and IRI (t0: 800 µmolIU/kgl [range 257-2700]; t1: 300 µmolIU/kgl [range 0-1498]; t2: 250 µmolIU/kgl [range 0-1498]; P <0.0001) decreased significantly during cabergoline treatment. Eight cats achieved diabetic remission between months 1 and 6 of cabergoline treatment (median time to achieve remission: 3 months [range 1-6]). Three cats experienced asymptomatic hypoglycemia.
Conclusions and relevance: Cabergoline was effective in normalizing IGF-1 concentration in 26% of cats. Cabergoline improved diabetes control and was associated with remission of DM in 35% of cases. Cabergoline could be a treatment option for cats with HST and DM, especially in those cases with a relatively small pituitary tumor.
Keywords: Acromegaly; cabergoline; diabetes mellitus remission; insulin-like growth factor 1.