Transcript THEME: HORMONAL DRUGS

HORMONAL DRUGS
Hormones are biologically active
substances, produced by the endocrine glands
and special cell groups in various tissues. They
play the most important role in the humoral
regulation of various functions of the body.
Moreover, some hormones are
neuromodulators.
The importance of hormones is particularly evident
when there is a hypofunction of the endocrine
glands. For example, failure of the pancreatic islet
cells leads to the development of diabetes mellitus,
parathyroid gland failure which causes
hypocalcaemia (associated with convulsions) and
insufficiency of the antidiuretic hormone of the
posterior pituitary lobe – diabetes insipidus. At the
same time there are diseases, associated with
increased production of hormones. Thus,
hyperfunction of the thyroid gland causes
hyperthyroidism (Basedow,s disease), excessive
production of the somatotropic hormone of the
anterior pituitary lobe – gigantism, acromegalia.
Failure of the endocrine glands is usually
treated with hormones. In such cases socalled replacement therapy is required; the
duration of the administration of
replacement hormones is determined by
the duration of the endocrine gland
hypofunction. Drugs that stimulate
hormone production can also be used for
the treatment of these conditions.
Hormonal drugs are obtained via synthetic routes as
well as from the organs and urine of animals (in the
latter case the activity of a number of drugs is
evaluated by biologic standardization and measured
in action units). Currently, genetic engineering
methods are widely used to obtain hormones. In
addition, a considerable number of natural hormone
derivatives and their synthetic substitutes have been
synthesized, and some of them are different from the
natural hormones in their structure.
When hyperhormonism use hormone antagonists, which block
the respective receptors or inhibit the synthesis of hormones.
The primary action of hormones is localized at the level of the
cytoplasmic membrane or intracellular. Some hormones (group of
peptides and proteins) interact with specific receptors on the
outer surface of cell membranes. Many of these receptors linked
to adenylate cyclase, activity change which largely determines
the content of intracellular cAMP. Most hormones stimulate
adenylate cyclase and increases cAMP. CAMP can also increase
due to inhibition of phosphodiesterase. However, because of the
hormones three-iodothyronine only, and then only at very high
concentrations. CAMP in turn activates protein kinase that
influences during different intracellular processes. In this way the
effect of corticotropin, thyrotropin, pituitary gonadotropins,
melanotsitstimuliruyushie hormones, parathyroid hormone,
calcitonin, glucagon.
Hormones may affect the grip and release of the intracellular
distribution of calcium ions, which may also act as a "mediator"
between membrane receptors and intracellular processes.
Furthermore, certain relationships established between cAMP and
kinetics of calcium ions.
Several hormones (proteins and peptides) act on membrane receptors,
adenylate cyclase is not associated with (HGH lactotropic hormone).
The question of "mediator" in this case is still open. Certain hormones
can affect fosfatidilinozitolny cycle, increasing the production of inositol
three-phosphate and diacylglycerol (for example, a hormone of the
hypothalamus, which stimulates the height gonadotropin-releasing
hormone, vasopressin).
Effect of hormones on cell membranes may also occur that they change
their permeability to other endogenous substances (e.g., insulin
facilitates entry of glucose into cells).
Several hormones penetrating the cell
membrane act intracellularly (e.g., steroids,
thyroid hormones). Steroids are an ¬ form a
complex with the sytoplasmic receptors
and are then transported into the cell
nucleus, where it appears their main effect.
In the cell nucleus it is activated DNA and
mRNA, which leads to the induction of
protein synthesis.
DRUGS hormone from the hypothalamus and pituitary
gland
The pituitary gland is composed of three shares: front,
back and middle Just noticeable. The front and middle
lobes contain glandular cells and grouped under the
name "anterior pituitary." Anterior lobe produces
adrenocorticotrop, growth, thyroid, follicle-stimulating,
luteinizing hormone and lactotrop. Their education and
liberation are regulated by special ¬ releasing
challenging (English to release-exempt), hormones and
hormone depressing (factors) of the hypothalamus. The
average share of some mammalian melanocyte secretes
hormones (α, β, γ) and also under the control of the
hypothalamus.
Synthesis and secretion of hormones regulated
by the hypothalamus and anterior pituitary of
feedback. This is manifested in the fact that the
activity of the centers of the hypothalamus and
the pituitary gland is dependent on the
concentration of circulating hormones ¬ new.
Decreasing the amount of hormones in the
blood stimulates hypotalamo-hypophysar
system, and is accompanied by a rise depressing
effect.