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, which may lead to exhaustion of the islets of Langerhans and diabetes mellitus.

Overproduction of counteracting hormones and insulin resistance

Progesterone is produced during the luteal phase of the bitch's oestrus cycle and 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.

Growth hormone excess is most commonly induced by excess progesterone/progestogens, causing Acromegaly. It may also rarely be caused by pituitary or hypothalamic neoplasia.

Hyperadrenocorticism (Cushing’s disease) or the administration of glucocorticosteroids stimulates gluconeogenesis. This increases blood glucose concentration which in turn Increases insulin secretion. This can lead to exhaust the islets of Langerhans.

Canine diabetes due to Non-Pancreatic Origin

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