Prostaglandins. Leukotrienes

Prostaglandins are a group of biogenic physiologically active
Substances contained in the organs and tissues of the body. The name is
From the Latin name of the prostate (glandula prostatica),
Where, as previously assumed, prostaglandins are formed.
On the chemical structure of prostaglandins (PG) belong to the class of fatty
Acids. At the heart of their structure is the so-called prostaglanda
[7- (2-octylcycloheptyl) heptanone] acid, consisting of a 20-membered
Carbon chain, part of which is included in the cyclopentane ring.
Biogenic precursors of prostaglandins in the body are
Arachidonic and some other unsaturated fatty acids (digomolino-
Lenic) contained in the phospholipids of cell membranes. Biosynthesis pro-
Staglandins occur with the participation of microsomal enzymes.
A number of natural prostaglandins have been isolated from animal tissues.
According to the peculiarities of the chemical structure, prostaglandins are divided into groups,
Having Latin indices E, F, A, B, etc., and on subgroups having
Additional numerical designations (PGE M1, PGE M2, etc.). Figures
The number of double bonds in the side chain of a molecule of that or
Another prostaglandin.
For medical purposes, prostaglandins were prepared initially from
Natural sources (some types of corals, etc.). At present
The time of prostaglandins and their derivatives are obtained synthetically.
Prostaglandins have a multifaceted physiological (pharmacological-
Activity). They believe that they are hormone-like
Substances (<local> hormones) that regulate cellular metabolism.
Characteristic is the effect of a number of prostaglandins on the contractor-
Smooth muscle activity, secretion, circulation (including
Microcirculation), as well as other body functions. Most Active
Prostaglandins of groups E, F and A, PGE1 and PGE2 have broncho-
And PGE M2 Aa is bronchoconstrictive; PGE M1 brakes
Secretion of gastric juice, release of hydrochloric acid and pepsin;
PGE M2 reduces peripheral vascular resistance and reduces artefacts.
Real pressure, increases capillary permeability; PGA M 1 and
PGA M2 also reduces vascular resistance and lowers arterial
pressure.
Vascular effects of prostaglandins are associated with their immediate
Effect on the smooth muscle of the vessels and the modulating effect on the
A nervous innervation. Prostaglandins, enhancing adrenergic
Influence, cause narrowing of blood vessels; Weakening adrenergic
Influence - their expansion. It is also believed that the action of prostaglandins
Is associated with an increase (or decrease) in intracellular content
CAMP.
Prostaglandins take part in the transmission of nerve impulses at different times.
Sections of the nervous system, exerting a modulating effect on the
Synaptic processes.
Prostaglandins of groups E and F exert a strong stimulating effect
On myometrium, which manifests itself in relation to both non-pregnant and
Pregnant womb at all stages of pregnancy.
Under physiological conditions they are of great importance for reproductive health.
Function; Are considered as "ovulation mediators"; Contribute to the
Regulation of implantation processes, the onset of labor and other activities.
Prostaglandins play an important role in the mechanism of action of a number of drugs.
Funds. It was found that acetylsalicylic acid, indomethacin,
Orthophene and other non-steroidal anti-inflammatory drugs inhibit
Biosynthesis and physiological activity of prostaglandins.
Initially, most attention was paid to physiological and pharmacological
The prostaglandins of group E and F were attracted to prostatic gland. Prostaglane-
Groups F and E have found application in medical practice as
<Mother> (oxytocic) drugs (see Means that stimulate muscular)
Fistula of the uterus). Based on prostaglandins, other
Pharmacological groups (see Alprostadil, Misoprostol).
At the present time, much attention is paid not only to prostaglandin-
Us, but also a number of related products of arachidonic acid metabolism.
It turned out that, depending on the path of enzymatic biotransformation
Arachidonic acid from it, various highly active compounds are formed.
With the participation of the cyclooxygenase enzyme, along with prostaglandins,
Prostacyclin (with the participation of prostacyclin synthetase) and thromboxanes
(With the participation of thromboxane synthetase).
Prostacyclin, synthesized primarily in the vascular endothelium, and
Also entering the bloodstream from the lungs, is particularly strong
An endogenous platelet aggregation inhibitor and an antiadherent.
Its antiaggregation effect is associated with activation of adenylate cyclase and
An increase in the content of cAMP in platelets. It also reinforces the anticoagulant
Lation effect of heparin. Prostacyclin has a high vasoconstriction
And hypotensive activity.
Thromboxane as opposed to prostacyclin has a strong proagrega-
And has a pronounced vasoconstrictor effect.
It is believed that the balance between prostacyclin and thromboxane plays an important role
Role in providing hemostatic balance and function of platelets and
That the violation of this equilibrium in the direction of exceeding the activity of thrombo-
The dignity promotes the development of thromboses and atherosclerotic changes
Vessels.
Under the influence of the enzyme 5-lipoxygenase in the process of metabolism
Arachidonic acid another group of highly active compounds is formed.
Leukotrienes (LT). They are named so because initially
They were discovered in leukocytes and have a conjugated triene structure.
The compounds of this group (LTV, LTS) play an important role in the development of
Inflammation and bronchiolospasm. LTS is a component of the so-called
Slowly reacting substance of anaphylaxis.
Leukotrienes, unlike prostaglandins, do not have a structure
Cyclic nucleus.
Prostaglandins, leukotrienes and related compounds are called
Eicosanoids, since they are derivatives of eicosanoic acids:
Eicosotrienium (dihomo- -linolenic), eicosotetraene
(Arachidonic), etc.
In connection with the high physiological activity of these endogenous soy-
From the moment of their discovery, identification of structure and synthesis
(70s) was the beginning of their use as a medicinal product
Means. Initially, prostaglandins F and E were used as
(See Dinoprost, Dinoprostone). Currently, different
The compounds of this group began to be used in other fields of medicine
(See Prostenon, Alprostadil, Misoprostol).
A lot of work is being done to create new medicines for
Based prostaglandins and prostacyclin (bronchodilator, antiagrega-
Antihypertensive, anti-sclerotic, etc.).
A search for antagonists of leukotrienes, calculated
To receive anti-inflammatory and bronchodilator drugs.