Hypothalamic Hormones And Their Functions: Table

2024 Author: Rachel Wainwright | [email protected]. Last modified: 2024-01-15 19:51

Hypothalamic hormones and their role in the regulation of the endocrine system

The content of the article:

Anatomy and physiology
What organs are affected
Functions of hypothalamic hormones
1. Oxytocin
2. Vasopressin
Video

In the regulation of the functions of the endocrine system and maintenance of water and electrolyte balance in the human body, an important role belongs to the hormones of the hypothalamus. Let's take a closer look at their functions.

The hypothalamus is an organ of the endocrine system that produces hormones that regulate the activity of the pituitary gland

Anatomy and physiology

The hypothalamus is located at the base of the brain under the thalamus and is the place where the interaction between the central nervous system and the endocrine system takes place. In its nerve cells, substances with a very high biological activity are formed. Through the capillary system, they reach the pituitary gland and regulate its secretory activity. Thus, there is a direct link between the production of hormones from the hypothalamus and the pituitary gland - in fact, they are a single complex.

The hypothalamus produces the following hormones:

thyroliberin (TRF);
corticoliberin (CRF);
folliberin (FRL);
luliberin (LRL);
prolactoliberin (PRL);
somatoliberin (CPR);
melanoliberin (MLR);
melanostatin (MYTH);
prolactostatin (PIF);
somatostatin (SIF).

By their chemical structure, they are all peptide, that is, they belong to a subclass of proteins, but the exact chemical formulas have been established for only five of them. Difficulties in their study are due to the fact that they are very few in the tissues of the hypothalamus. For example, in order to isolate only 1 mg of thyroliberin in pure form, it is necessary to process about a ton of hypothalamus obtained from 5 million sheep!

What organs are affected

Liberins and statins produced by the hypothalamus reach the pituitary gland through the portal vascular system, where they stimulate the biosynthesis of tropic pituitary hormones. The latter, with the blood flow, reach the target organs and exert their effect on them.

Let's consider this process in a simplified and schematic manner.

The releasing factors reach the pituitary gland through the portal vessels. Neurophysin stimulates the cells of the posterior pituitary gland, thereby increasing the release of oxytocin and vasopressin.

The rest of the releasing factors affect the anterior pituitary gland. The scheme of their influence is presented in the table:

Releasing factor	Tropic hormone produced by the pituitary gland	Target organ
Corticoliberin	Adrenocorticotropin	Adrenal glands
Tyroliberin	Thyrotropin	Thyroid
Somatoliberin	Somatotropin	Growing tissues and organs
Prolactoliberin	Prolactin	Breast
Folliberin	Follicle-stimulating hormone	Ovaries, uterus, prostate gland, seminal vesicles
Luliberin	Luteinizing hormone	Ovaries, uterus

Functions of hypothalamic hormones

To date, the biological functions of the following hypothalamic releasing factors have been most fully studied:

Gonadoliberins. They have a regulatory effect on the production of sex hormones. Provide a correct menstrual cycle and form libido. It is under their influence in the ovary that the ovum matures and leaves the graaf bubble. Insufficient secretion of gonadoliberin leads to a decrease in potency in men and infertility in women.
Somatoliberin. The secretion of growth hormone is influenced by the hypothalamus by the release of somatoliberin. A decrease in the production of this releasing factor causes a decrease in the release of somatotropin by the pituitary gland, which ultimately manifests itself in slow growth, dwarfism. Conversely, an excess of somatoliberin promotes high growth, acromegaly.
Corticoliberin. Serves to enhance the secretion of adrenocorticotropin by the pituitary gland. If it is produced in insufficient quantities, then the person develops adrenal insufficiency.
Prolactoliberin. It is actively produced during pregnancy and lactation.
Tyroliberin. Responsible for the formation of thyrotropin by the pituitary gland and an increase in thyroxine, triiodothyronine in the blood.
Melanoliberin. It regulates the formation and decomposition of the melanin pigment.

The physiological role of oxytocin and vasopressin is much better understood, so let's talk about this in more detail.

Oxytocin

Oxytocin can have the following effects:

promotes the separation of milk from the breast during lactation;
stimulates uterine contractions;
enhances sexual arousal in both women and men;
eliminates feelings of anxiety and fear, helps to increase trust in a partner;
slightly reduces diuresis.

The results of two independent clinical studies, conducted in 2003 and 2007, showed that the use of oxytocin in the complex therapy of autistic patients led to the expansion of the boundaries of emotional behavior in them.

A group of Australian scientists found that intramuscular administration of oxytocin made experimental rats immune to the action of ethyl alcohol. Currently, these studies are ongoing, and experts suggest that it is possible that oxytocin will be used in the future in the treatment of people with alcohol dependence.

Vasopressin

The main functions of vasopressin (ADH, antidiuretic hormone) are:

narrowing of blood vessels;
water retention in the body;
regulation of aggressive behavior;
increased blood pressure by increasing peripheral resistance.

Dysfunction of vasopressin leads to the development of diseases:

Diabetes insipidus. The pathological mechanism of development is based on insufficient secretion of vasopressin by the hypothalamus. The patient's diuresis sharply increases due to a decrease in the reabsorption of water in the kidneys. In severe cases, the daily amount of urine can reach 10-20 liters.
Parkhon's syndrome (syndrome of inappropriate secretion of vasopressin). Clinically manifests itself as lack of appetite, nausea, vomiting, increased muscle tone and impaired consciousness up to coma. With the restriction of water intake into the body, the condition of patients improves, and with abundant drinking and intravenous infusions, on the contrary, it worsens.