Pituitary gland protective bony enclosure called the sella turcica. It is composed of three lobes: anterior, intermediate, and posterior. In many animals, these three lobes are distinct.The intermediate is avascular and almost absent in human beings. The intermediate lobe is present in many lower animal species, in particular in rodents, mice and rats, that have been used extensively to study pituitary development and function. In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary, which is an extension of the hypothalamus. The anterior pituitary arises from an invagination of the oral ectoderm and forms
Pituitary stalk tract. It has been thought that the pituitary stalk may become compressed due to suprasellar tumors in the pars tuberalis region, and that the resulting compression may cause hyperprolactinemia. This phenomenon has been described as the stalk effect or pituitary stalk compression syndrome. However, at least one article suggests that the increase in prolactin in these cases may instead be caused by the tumor's secretion of preprotachykinin A-derived tachykinins, substance P, and/or neurokinin A. Damage to the pituitary stalk blocks the release of antidiuretic hormone, resulting in polydypsia (abusive water intake) and polyuria (excessive urination). Pituitary stalk The pituitary stalk