Neuroendocrinology | Specialists and Information

The two most important structures in neuroendocrinology are the hypothalamus and the pituitary gland. Both are located in the brain and control vital functions from there.

The hypothalamus is responsible for:

• Hunger
• Thirst
• The day-night cycle
• Body temperature, and
• blood pressure

All of these functions are regulated by increased or decreased secretion of the corresponding hormones.

Unlike other hormones, the hormones produced by the hypothalamus are not distributed throughout the body via the bloodstream. Instead, hypothalamic hormones act on the pituitary gland by regulating the release of hormones by the pituitary gland.

These pituitary hormones control a wide variety of bodily functions: from the thyroid and adrenal glands to milk production in the female breast.

 

 

Functions of the Hypothalamus and Pituitary Gland @ ellepigrafica /AdobeStock

Neuroendocrinologists are medical specialists who focus on diseases caused by a malfunction of the neuroendocrine system. 

Causes can include, for example, brain tumors or brain injuries. 

Key areas of neuroendocrinology include, for example:

• Tumors: such as pituitary adenoma (benign tumor of the pituitary gland) and multiple endocrine neoplasia type I (concurrent occurrence of benign pituitary tumors and benign parathyroid tumors)
• Impaired hormone production (hormone deficiency) following traumatic brain injury
• Thyroid and parathyroid disorders: Such as hyperthyroidism (overproduction of thyroid hormone), hypothyroidism (insufficient supply of thyroid hormone), and hypoparathyroidism (low calcium levels due to reduced parathyroid hormone production by the parathyroid glands)
• Adrenal disorders: such as hypercortisolism (Cushing’s syndrome; increased cortisol production), hypocortisolism (Addison’s disease; adrenal insufficiency), hyperaldosteronism (Conn’s syndrome; excessive production of aldosterone in the adrenal cortex)
• Metabolic disorders: Such as hypercalcemia syndrome (elevated calcium levels, usually due to increased calcium release from the bones) and osteoporosis, diabetes mellitus (diabetes), and obesity
• Disorders of sex hormone production: such as polycystic ovary syndrome (PCOS)
• Hormonal issues associated with psychiatric disorders
• Disorders of sex development and transsexuality

PCOS can lead to menstrual irregularities, hair loss, and infertility in women @ freshidea /AdobeStock

The doctor begins with a comprehensive medical history. 

This includes asking about:

• Symptoms
• Lifestyle 
• Medication use and 
• medical history, including that of immediate family members

This is followed by a physical examination. Both provide the doctor with initial indications as to whether a hormonal disorder is the cause of the patient’s symptoms.

This is usually followed by laboratory tests to measure the levels of various hormones in the blood (hormone profile, hormonal testing). 

Endocrinological laboratory diagnostics usually provide a fairly accurate picture of whether:

• the disorder is located within or outside the brain and 
• What disorder might be present

As part of endocrinological functional tests, the doctor can further investigate and narrow down the cause of the dysfunction.

Functional tests include:

• Stress tests (oral glucose tolerance test)
• Stimulation tests and 
• Inhibition tests

In these tests, the doctor administers specific hormones or substances to the patient and observes the body’s response.

Imaging techniques, such as CT, MRI, or ultrasound, reveal pathological changes in the endocrine glands and the brain. For example, MRI is very effective at visualizing pituitary tumors.

The causes of neuroendocrine disorders are diverse.

Doctors generally distinguish between:

• Hypofunction and
• hyperfunction

In hypofunction, the body produces too few or no hormones. This affects all regulatory cycles controlled by that hormone.

In the case of hyperfunction, there is a pathologically elevated release of hormones, usually due to structural changes in the tissue. All disorders can affect either a single hormone or multiple hormones.

In some cases, neuroendocrine hypofunction is caused by a genetic defect and is therefore congenital. Treatment involves administering the missing hormones to prevent the resulting impairments. 

Depending on the specific genetic defect, treatment may be necessary only temporarily or for life. The same applies if tissue has been destroyed by an accident or surgery.

The cause of neuroendocrine hyperfunction of the pituitary gland is usually a tumor. In most cases, this is a benign tumor. Treatment depends primarily on the tumor’s size and growth rate. 

If the tumor grows rapidly, surgery is usually the best solution. This also applies to hypophysitis, an inflammation of the pituitary gland. In some cases, however, medication alone may be sufficient.

Last but not least, neuroendocrinologists are key points of contact for transgender gender reassignment. They monitor and manage hormone therapy. They ensure that the transition in sex hormones proceeds as gently as possible for the body and without complications.

Endocrinologists administer gender-affirming hormone therapy @ Matthias Stolt /AdobeStock

Neuroendocrinologists often hold board certification in internal medicine and endocrinology and diabetology. 

They may also be board-certified in neurology and have completed additional training in the field of neuroendocrinology.

If surgical procedures are required, the treating physicians are usually:

• specialists in neurosurgery (for procedures involving the brain) or
• Specialists in general surgery or visceral surgery

A physician licensed to practice in Germany can complete specialty training after earning a medical degree. Depending on the specific specialty, this requires five to six years of practice. During this time, the physician must perform a specified number of diagnostic procedures and treatments.

As a result, the neuroendocrinologist gains in-depth knowledge in all areas of the diagnosis and treatment of neuroendocrine diseases.