ANIMAL-MODELS OF CUSHINGS-DISEASE

Cushing's disease, defined as hyperadrenocorticism resulting from excessive secretion of pituitary ACTH, occurs spontaneously and quite commonly in dogs and houses. In dogs, as in humans, the disease is usually associated with a small tumor of the pituitary pars distalis. However the disease may arise occasionally (dogs) or exclusively (horses) from tumors or hyperplasia of the pituitary pars intermedia. In dogs, pars intermedia tumors may arise from one of two proopiomelanocortin-containing cell types that ave present in normal tissue.