Canine diabetes of Non-Pancreatic Origin

Diabetes mellitus in dogs can be caused by conditions other than primary dysfunction of the endocrine pancreas.

Obese dogs

• The sensitivity of tissue receptors to insulin is decreased by obesity
• This increases the demand for insulin resulting in hyperglycaemia along with high plasma insulin concentrations
• May lead to exhaustion of the islets of Langerhans and diabetes mellitus

Overproduction of counteracting hormones and insulin resistance

Growth hormone excess– in dogs this is most commonly induced by excess progesterone/progesterones. May also rarely be caused by pituitary or hypothalamic neoplasia.

Progesterone– produced during the luteal phase of the bitch’s oestrus cycle induces the production of growth hormone by the mammary glands. Growth hormone counteracts insulin action.

The administration of progestagens, e.g. for oestrus suppression or as a treatment (through their glucocorticosteroid actions) for skin disease, may also induce growth hormone excess leading to diabetes mellitus.

Hyperadrenocorticism (Cushing’s disease) or the administration of glucocorticosteroids

• Glucocorticosteroids stimulate gluconeogenesis
• Increase blood glucose concentration
• Increase insulin secretion
• Exhaust the islets of Langerhans

About 10% of canine Cushing’s disease cases are complicated by diabetes mellitus.