The human pituitary gland is oval shaped, about 1 cm in diameter, 0.5–1 gram (0.018–0.035 oz) in weight on average, and about the size of a kidney bean.

Hormones secreted from the pituitary gland help to control growth, blood pressure, energy management, all functions of the sex organs, thyroid gland, metabolism, as well as some aspects of pregnancy, childbirth, breastfeeding, water/salt concentration at the kidneys, temperature regulation, and pain relief.

The intermediate lobe is present in many animal species, particularly in rodents, mice, and rats, which have been used extensively to study pituitary development and function.

Endocrine cells of the anterior pituitary are controlled by regulatory hormones released by parvocellular neurosecretory cells in the hypothalamic capillaries leading to infundibular blood vessels, which in turn lead to a second capillary bed in the anterior pituitary.

With special stains attached to high-affinity antibodies that bind with distinctive hormone, at least 5 types of cells can be differentiated.

The magnocellular neurosecretory cells, of the supraoptic and paraventricular nuclei located in the hypothalamus, project axons down the infundibulum to terminals in the posterior pituitary.

The release of pituitary hormones by both the anterior and posterior lobes is under the control of the hypothalamus, albeit in different ways.

Somatotropes: Corticotropes: Thyrotropes: Gonadotropes: Lactotropes: These hormones are released from the anterior pituitary under the influence of the hypothalamus.

Infundibulum: A downward extension from the neuroectoderm of the diencephalon in the brain, which forms the posterior pituitary (neurohypophysis).

Formation of the Posterior Pituitary (4th to 8th week): The infundibulum from the diencephalon elongates downward, forming a stalk that connects with Rathke’s pouch.

Specialized cells from the hypothalamus, known as pituicytes, migrate to the posterior pituitary, where they help store and release hormones such as oxytocin and vasopressin.

The posterior pituitary functions primarily in storage, as it stores hormones produced by the hypothalamus and releases them into the bloodstream.

Final Structural Differentiation The pituitary gland achieves its final form, including the complete separation of anterior and posterior lobes, by the end of the first trimester The gland remains connected to the hypothalamus by the pituitary stalk, allowing it to integrate signals from the brain and regulate various endocrine functions in the body.

Critically, pituitary gland growth during adolescence can be altered by early life stress such as childhood maltreatment or maternal dysphoric behavior.

[17] Additionally, a correlation between pituitary gland volume and Social Anxiety subscale scores was identified which provided a basis for exploring mediation.

Again controlling for age, sex, and BMI, DHEA and DHEA-S have been found to be predictive of larger pituitary gland volume, which was also associated with increased ratings of social anxiety.

[17] This research provides evidence that pituitary gland volume mediates the link between higher DHEA(S) levels (associated with relatively early adrenarche) and traits associated with social anxiety.

[18] The expression glandula pituitaria and its English equivalent pituitary gland can only be justified from a historical point of view.

In lungfish, it is a relatively flat sheet of tissue lying above the anterior pituitary, but in amphibians, reptiles, and birds, it becomes increasingly well developed.

Closely associated with the pouch are three distinct clusters of glandular tissue, corresponding to the intermediate lobe, and the rostral and proximal portions of the anterior pituitary.

[27] Most armadillos also possess a neural secretory gland very similar in form to the posterior pituitary, but located in the tail and associated with the spinal cord.

The intermediate lobe produces melanocyte-stimulating hormone (MSH), although this function is often (imprecisely) attributed to the anterior pituitary.