Plasma concentrations of insulin-like growth factor (IGF)-1 were examined in dogs suffering from food-responsive diarrhea (group FRD) or inflammatory bowel disease (group IBD) before and after treatment and compared with IGF-1 values in healthy dogs (group C). Blood of 76 dogs was sampled (FRDbefore treatment, n = 23; IBD before treatment, n = 11; C, n = 42) and after treatment (FRD, n = 15; IBD, n= 8) with a hypoallergenic diet combined with (group IBD) or without prednisolone (group FRD). A clinical score (Canine IBD Activity Index = CIBDAI) was applied to judge the health status in all dogs. Plasma concentration of IGF-1, of total protein, albumin, glucose, urea, non-esterified fatty acids (NEFA), and of the acute phase protein haptoglobin was measured in all dogs. The CIBDAI scores decreased during the treatment period in FRD and IBD (P < 0.05). IGF-1 concentrations were positively correlated with body weight (BW) (r_sp = 0.65, P < 0.001) and values of IGF-1 were therefore normalized with BW. IGF-1/BW ratios were lower in FRD and IBD before treatment than in C (P < 0.01).
IGF-1/BW ratios increased in FRD (P < 0.05) dogs during treatment. Plasma glucose concentration was lower in FRD dogs before treatment than in C (P < 0.05), and NEFA concentrations were higher in FRDdogs before and after treatment than in C (P < 0.001). Haptoglobin concentrations were higher in IBD dogs before and after treatment than in all other groups (P < 0.05). In conclusion, chronic enteropathies reduce the plasma IGF-1 status in dogs. The increase of the IGF-1/BW ratio after treatment suggests that plasma IGF-1 concentration may help to judge the outcome of chronic enteropathies in dogs.