Hypothalamic–pituitary–thyroid axis control over the hypothalamus as well as anterior pituitary, thus controlling the release of both TRH from hypothalamus and TSH from anterior pituitary gland. The HPA, HPG, and HPT axes are three pathways in which the hypothalamus and pituitary direct neuroendocrine function. Thyroid homeostasis results from a multi-loop feedback system that is found in virtually all higher vertebrates. Proper function of thyrotropic feedback control is indispensable for growth, differentiation, reproduction and intelligence. Very few animals (e.g. axolotls and sloths) have impaired thyroid homeostasis that exhibits a very low set-point that is assumed to underlie the metabolic and ontogenetic anomalies of
Pituitary pars intermedia dysfunction Pituitary pars intermedia dysfunction Pituitary pars intermedia dysfunction (PPID), or equine Cushing's disease, is an endocrine disease affecting the pituitary gland of horses. It is most commonly seen in older animals, and is classically associated with the formation of a long, wavy coat (hirsutism) and chronic laminitis. Unlike the human and canine forms of Cushing's disease, which most commonly affect the pars distalis region of the pituitary gland, equine Cushing's disease is a result of hyperplasia or adenoma formation in the pars intermedia. This adenoma then secretes excessive amounts of normal products, leading to clinical signs. The pituitary gland consists