HORIONYCHESKY GONADOTROPHIN (Greek chorion cover, afterbirth; Greek gone birth, seed + expert! [yop] gland + tropos direction; a synonym choriogonadotropin) — the specific hormone of pregnancy synthesized by syncytial cells of a trophoblast of a placenta, regulating products of estrogen and progesterone a yellow body and thus promoting preservation of pregnancy.
J. Halban in 1905 and Ashner (V. of Aschner) in 1913 assumed that a placenta (see) is a source of biologically active agents. Assumption of existence of X. Hee dew stated (T. Hirose) in 1920. The first message on existence in urine of pregnant large amounts of hormone with luteinizing gonadotropic activity was made 3. Ash-geymom.i B. Tsondek in 1927. In 1930 Mr. Philipp (E. Philipp) pointed to a placental origin of hormone.
X. 24 hours represent difficult heterogeneous glycoprotein connection with the period of semi-life. As a part of X. there are proteins, hexoses, amine groups and neuraminic to - that. In structure of X. are allocated and - and (3 subunits, their amino-acid sequence is specified. Molecular structure of X. differs from structure of luteinizing hormone (see) higher content sialine to - you in a carbohydrate component of glycoproteins, and also composition of 28 — 30 terminal amino acids on the carboxyl end [j-subunits. Molecular weight is X. makes 36 700, an isoelectric point (see) at pH 4,5.
X. produce sintsitotrofo-
0 1 as*ta of a placenta only of the person and primacies. The mechanisms controlling its biosynthesis, accumulation and allocation are unknown. In a placenta it is found specific to X. adenylatecyclase that allows to assume a miss regulation of hormone. Secretion of X. does not depend on a hypothalamus and hemadens.
Content of r-subunit is X. in blood and urine is defined since 8th day after fertilization. Maximum secretion of X. it is observed between the 9th and 12th weeks of pregnancy and reaches 2 — 3 mg a day then concentration of hormone quickly decreases and remains until the end of pregnancy at the low level. In 10 days after the delivery X. in blood and urine it is not found. Concentration of hormone in blood serum same, as well as in placental fabric that demonstrates its continuous receipt in blood. X. it is allocated with urine in not changed look.
On biol. to action of X. it is close to pituitary gonadotrophins (see. Gonadotropic hormones) with the prevailing luteinizing effect. X. communicates membrane receptors, the number to-rykh is regulated by concentration of hormone. Further adenylate-tsiklaznaya system is activated and carried out biol. the action typical for proteinaceous and peptide hormones (see). Role and function X. during pregnancy consist in maintenance of existence and the subsequent development of a yellow body; the inhibiting influence on products of follicle-stimulating hormone that prevents emergence of cyclic menstrual changes in an endometria and keeps pregnancy; stimulations of secretion of testicular androgens of a fruit in the first weeks of pregnancy; regulation of synthesis of steroids internal germinal zone of bark of adrenal glands of a fruit.
At introduction to nonpregnant women of X. stimulates an ovulation (promotes transition of the developed follicle in, the yellow body and extends life time of a yellow body).
Men have the X introduction. stimulates secretion of testosterone with intersticial cells of testicles therefore the spermatogenesis is stimulated and puberty accelerates. X. promotes lowering of the testicles which did not fall to a scrotum thanks to strengthening of secretion of testosterone and direct action on connecting fabric of the inguinal channel.
Presence of X. in urine is the precursory diagnostic character of pregnancy for the first time established 3. Ashgeym and B. Tsondek (see Ashgeym — Tsondeka reaction). At insufficient secretion of X. there can come abortion (see the Misbirth). There are messages on hypersecretion of X. at the pregnancy proceeding with toxicosis (see Toxicoses of pregnant women), a nephropathy that connect with a hyperactivity of chorion.
X. comes to light in blood and urine at 15 — 20% of the women applying vnutrikhmatochny contraceptives that demonstrates possible synthesis of X. blastocytes before pregnancy. Sharp increase in contents of X. in urine it is observed at a trophoblastic disease (see). X. it is found also in men at malignant teratomas of testicles. Besides, X. can come to light at various other malignant tumors (cancer of a lung, stomach, pancreas, mammary glands, a melanoma, a multiple myeloma).
For qualitative test of X. in urine use various modifications biol. method. Galli-Maynini's reaction (see Galli-Maynini reaction), immunological tests (a gem-agglyutinatsionny method the Look — Gemzellya), tracer techniques is most widespread (generally in research). Also various quantitative methods are applied.
The domestic industry drug X is produced. — a gonadotrophin chorionic for injections, received from urine of pregnant women, activity on 500, 1000, 1500 and 2000 PIECES, in the form of the lyophilized powder. To women of X. appoint at disturbances of a menstrual cycle (see) and infertility (see), connected with lack of an ovulation and insufficiency of a yellow body (but at sufficient oestrogenic function of ovaries), dysfunctional uterine bleedings (see). Drug is shown to men at a secondary hypogonadism (a cryptorchism, a cerebral and pituitary nanism, an adiposagenital syndrome). At a cryptorchism (see) it apply to stimulation of process of lowering of testicles in a scrotum, and also as preoperative preparation and in the postoperative period for improvement of a functional condition of gonads. In the diagnostic purposes use for assessment of a functional condition of gonads and "at differential diagnosis of an anorkhizkhm and bilateral belly cryptorchism.
The drug is administered intramusculary. The dose depends on character, disease severity and age of the patient. At anovulatory cycles (see) appoint 1000 — 1500 PIECES daily or every other day within 5 — 6 days since 12th day of a cycle; at insufficiency of a yellow body — on 1500 PIECES every other day between the 12th and 23rd day of a cycle (for artificial stimulation of an ovulation of X. enter once 3000 — 5000 PIECES). At a cerebral and pituitary nanism (see Dwarfism) apply at youthful age after closing of regions of growth 500 — 1000 PIECES of 1 — 2 time a week within 1 — 2 month with repeated courses. At a cryptorchism at children under 5 years on 250 — 500 PIECES on an injection,
from 5 to 10 years on 500 — 1000 PIECES, are more senior than 10 years on 1500 PIECES 2 times a week, 10 injections on a course. At the expressed positive, but incomplete or unstable effect conduct
1 more course of treatment. In order to avoid antibody formation to drug the interval between courses shall make 1V2 — 2 month. For stimulation of a spermatogenesis appoint up to 3000 PIECES every other day courses during
3 — 4 weeks.
At use of a chorionic gonadotrophin allergic reactions are sometimes observed. At prolonged uncontrolled treatment emergence of signs of early puberty (see), premature closing of regions of growth is possible. Drug is contraindicated at inflammatory diseases of the sexual sphere, hormonal and active tumors of gonads, an ectopia of a small egg. Its use in the absence of gonads is inexpedient.
Bibliography: Dimitrovd. Ya. A chorial gonadotrophin of the person, the lane with bolg., M., 1979, bibliogr.; R about z about in with to both y I. S. and d river. Excretion of a chorionic gonadotrophin, estriol and pregnandiol during normal pregnancy, Akush. and ginek., No. 8, page 17, 1966; Starkova H. T. Bases of a clinical aidrologiya, M., 1973; Endocrinology and metabolism, ed. by Ph. Felig a. o., p. 683, N. Y. a. o., 1981; Hormones in blood, ed. by of Page H. Gray a. V. H. T. James, v. 1, p. 363, L. a. o., 1979. A. G. Mazowiecki, T. JI. Kurayeva.