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Endocrinology

The slowed-down puberty

Table of contents
The slowed-down puberty
Puberty delay reasons
Stages of development of a reproductive system
Treatment of the patient with a puberty delay

Close concept: hypogonadism

Discussing treatment of cases of a delay of puberty, it is necessary to consider physiological mechanisms of sexual development which depends on secretion increase by a hypothalamus of the factors (rileasing-hormones) stimulating allocation of gonadotropic hypophyseal hormones. In order that there was an activation gipotalamo - a pituitary and sexual axis, apparently, a certain critical level of a maturity of the central nervous system is necessary. This maturity is partly connected with increase of sensitivity of luteinizing hormone to gonadotropic rileasing-hormones. It is supposed that the person has several periods of activation gipotalamo - a pituitary reproductive system. The first period — pregnancy when there is a differentiation of a floor of a germ, the second period — early children's age, the third period — teenage age. During these periods probably the neurohumoral centers are especially sensitive to an inhibiting effect of the circulating sexual steroids. This sensitivity at achievement of puberty decreases, at the expense of it there is "inclusion" of secretion of the hypothalamic regulating hormones. In recent years researchers attach the increasing significance to effect of biogenic amines of the central nervous system, including noradrenaline and dopamine which participate as neuromediators in gipotalamo - pituitary and gonadotropic regulation and secretion. These mediators are probably necessary for control and "start" of pituitary secretion of FSG and LG. The serotonin role as the antagonist of these substances is still not established.

Silman and soavt. reported that with approach of puberty at boys decrease in level of melatonin in plasma can be observed. Thus, melatonin can suppress puberty "start" to term.
We made a number of experiments on rodents and embryos of mammals. To unripe one-day rats antibodies to the gonadotropic hormone of a ram received by immunization of rabbits the crude mutton gonadotropic hormone were entered. At hypodermic administration of this substance within 10 days observed reduction of the sizes of ovaries and a uterus. After the termination of its introduction essential increase in secretion of endogenous gonadotropic hormone and premature puberty at experimental animals is noted. The first signs of maturing of a vagina and cyclic change of products of estrogen appeared at experimental animals at the age of 22 — 25 days, and in control group of the same dung — at the age of 45 — 50 days.

The maintenance of gonadotrophins in a hypophysis of the animals receiving for 10 days of an antibody to gonadotropic hormone significantly increased and was comparable with the maintenance of gonadotrophins in a hypophysis of animals of control group in 10 days after castration. Besides, we found out that gonadotropic activity of a hypophysis of a fruit of cattle exceeds activity of hypophyses of young bull-calves or adult cows. Thus, the impression is made that the hypophysis of unripe animals or a fruit contains high concentration of gonadotrophins and it is capable to cosecrete at the corresponding stimulation gonadotropic hormones. But, as a rule, secretion of gonadotrophins is suppressed first of all due to inhibitory action of products of gonads. These products are similar to estrogen and probably cosecrete directly unripe ovaries.

Existence of hormonal activity of ovaries of unripe animals was revealed us experimentally at introduction of antibodies to gonadotropic hormone of a ram to one-day rats for 10 days and comparison of the sizes of a uterus at them with a uterus size at similar animals of control group which executed castration 10 days ago. For the 11th day after castration or the beginning of introduction of anti-gonadotropic antibodies in both groups of animals essential reduction of the sizes of a uterus, and in group of the animals receiving antibodies to hormone and reduction of the sizes of ovaries in comparison with group of the animals who were not exposed to any influence was revealed. These data confirm existence in ovaries of some cosecreted substances with uterotropny action. Secretion by ovaries of the hormones supporting growth of a uterus probably is regulated by activity of a hypophysis as it turned out that ovaries at the animals receiving anti-gonadotropic antibodies appeared significantly less, than at control animals. In process of maturing with age of a hypothalamus synthesis and secretion, gonadotropic rileasing-hormones begins, puberty begins after that. In other words, with age the hypothalamus ceases to be inhibited by hormones of gonads.



 
"Diffusion toxic craw   Excess of estrogen"