Evaluation of circulating concentrations of glucose homeostasis biomarkers, progesterone, and growth hormone in healthy Elkhounds during anestrus and diestrus

Abstract

To investigate whether circulating concentrations of biomarkers of glucose homeostasis, progesterone, and growth hormone in healthy female Elkhounds differ during diestrus and anestrus and to compare those findings with data from dogs of other breeds. 22 healthy female dogs of Elkhound breeds (known to have a high incidence of diestrus-associated diabetes mellitus) and 18 healthy female non-Elkhound dogs. For each dog, a blood sample (12 mL) was collected once during anestrus and once 2 to 8 weeks after cessation of estrual bleeding. Serum or whole blood samples were analyzed for glucose, growth hormone, insulin-like growth factor-1, C-peptide, fructosamine, and glycated hemoglobin A1c concentrations. Homeostasis model assessments (HOMAs) of pancreatic beta-cell function and insulin secretion were calculated. In Elkhounds, C-peptide concentration and the HOMA for beta-cell function (markers of insulin secretion) were higher in samples obtained during diestrus, compared with findings in samples obtained during anestrus. The HOMA for insulin sensitivity was lower (albeit not significantly) during diestrus than it was during anestrus in Elkhounds. Markers of insulin secretion and sensitivity were similar during anestrus and diestrus in the dogs of other breeds. Serum progesterone concentrations were greater during diestrus than during anestrus in Elkhounds and non-Elkhound dogs. All other variables did not differ between diestrus and anestrus within or between the 2 breed groupings. Results provided evidence that circulating insulin concentrations during diestrus are higher than those during anestrus in Elkhounds, which could contribute to development of diestrus-associated diabetes mellitus.