Pituitary gland

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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The pituitary gland is the pituitary gland - the interface between the endocrine system and the nervous system. In the pituitary gland, almost all of the important hormones that occur in the periphery of the body are partly produced and secreted, partly only stored and then released. Read everything important about the pituitary gland: function, structure and disorders that can occur in the event of a malfunction!

What is the pituitary gland?

The pituitary gland is an important hormonal gland in the brain. It is divided into two areas:

Adenohypophysis (anterior pituitary gland, HVL): contains glandular tissue (is hormone-active); makes up three quarters of the organ;
Neurohypophysis (posterior pituitary gland, HHL): contains nerve tissue (nerve fibers and neuroglia).

There is a small intermediate lobe (pars internedia) between the anterior and posterior lobes of the pituitary gland.

Both areas - adenohypophysis and neurohypophysis - are supplied by different vessels that enter the pituitary gland and form a vascular network inside. Blood flows through a portal vein system from the hypothalamus via the pituitary stalk (infundibulum) to the pituitary gland.

What is the function of the pituitary gland?

The pituitary gland produces and secretes various important hormones. The secretion is controlled by various releasing (release) and inhibiting (inhibiting) hormones of the hypothalamus.

In the anterior lobe of the pituitary gland, the following pituitary hormones are produced and secreted:

Somatotropin (STH): produced in Alpha-1 cells; as a growth hormone important for normal height growth;
Corticotropin (ACTH): produced in the basophilic beta cells; stimulates the adrenal cortex to grow as well as to form and secrete glucocorticoids, which have an indirect influence on the carbohydrate metabolism
Thyrotropin (TSH): also produced in the basophilic beta cells; controls the function of the thyroid gland
Lipotropin: has a lipolytic effect (fat-breaking down) and thus influences the fat metabolism
Follicle-stimulating hormone (FSH): together with luteinizing hormone (LH), it promotes follicle maturation in women and sperm formation (spermatogenesis) and the development of tubules in men
Prolactin (PRL): is formed from the eighth week of pregnancy and acts on the mammary gland and milk production

The posterior lobe of the pituitary stores the following hormones, which are produced by the pituitary nuclei of the hypothalamus:

Oxytocin: causes the uterine muscles to contract during childbirth (triggering labor) and the muscle cells of the mammary gland (stimulating milk secretion)
Vasopressin or adiuretin (ADH): inhibits the excretion of water via the kidneys (antidiuretic effect) and constricts the blood vessels

These hormones stored in the posterior lobe of the pituitary gland are passed on from there via the portal vein circulation to the body's circulation.

Where is the pituitary gland located?

The pituitary gland is located in the pituitary pit, the depression of the Turkish saddle. With its funnel-shaped stem, the pituitary gland hangs on the floor of the diencephalon.

What problems can the pituitary cause?

An overfunction of the alpha-1 cells in the anterior pituitary gland leads to gigantic stature in adolescents in whom the growth plates are not yet open. In adults, acromegaly develops - an enlargement of the nose, chin, fingers, and toes.

A benign tumor of the anterior pituitary, a pituitary adenoma, is the most common disease of the pituitary gland. It can consist of different cell types.If the adenoma is hormone-active, the pituitary gland produces excessive amounts of the hormone that the cells in question produce - with a correspondingly increased hormone effect. The most common of these is the prolactinoma, which releases excessive prolactin. In women it comes to milk flow and no menstruation, in men to an androgen deficiency and infertility.

A pituitary adenoma can also be hormonally inactive. Then you only notice it through its space occupation and its possible effects. The enlargement of the pituitary gland expands the Turkish saddle, which affects the directly adjacent optic chiasm (junction of the optic nerves) in the central fossa. The direct consequences are bitemporal hemianopia (the outer field of vision in both eyes is narrowed) and a decrease in vision when the optic nerve is damaged by the growth and pressure of the adenoma.

Hypopituitarism is an underactive function of the anterior pituitary gland due to inflammation, tumors, or medication. As a result, the secretion of growth, thyroid and sex hormones is reduced or stopped entirely. This disrupts growth, physical development, metabolism and fertility.

In diabetes insipidus there is a deficiency in the hormone ADH, which is stored in the posterior lobe of the pituitary gland. The body's water balance is then disturbed. Symptoms are lack of fluids due to increased urine production and excretion, constant feeling of thirst, dry skin and mucous membranes, constipation, sleep disorders, irritability and cramps up to collapse.

The adrenal cortex is also controlled via the pituitary gland. If the function of the pituitary gland is restricted, the adrenal cortex also produces fewer hormones.

If the pituitary function is impaired, if TSH and somatotropin, which indirectly increase the blood sugar level, are reduced, then hypoglycaemia (low blood sugar) occurs.

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