The relationship with the thymus gland endocrine glands
Endocrinology / / May 01, 2016
Many researchers observed acceleration in the growth of tadpoles delayed their metamorphosis under the influence of thymus extracts.The accelerating impact on the growth of the thymus gland was proved in experiments on puppies, kittens, rabbits and other animals.A similar effect was observed when feeding chickens thymus gland.On the contrary, thymectomy results in stunted growth and skeletal changes resembling those in rickets.The mechanism of action of stimulating the thymus growth remains unclear.Some investigators growth accelerating action of the prostate is associated with its hormonal activity, others to the presence in it of substances involved in the growth process (glutathione, cysteine, ascorbic acid).
Some researchers observed hypoplasia of the thymus after hypophysectomy and believed that the pituitary gland produces a hormone that has timotropnoy activity.However, hypoplasia of the thymus gland, which develops immediately after hypophysectomy, is not due to loss timotropnoy pituitary activ
involution of the thymus gland by the action on the organism of various emergency stimuli, when a sharp increase in corticoid adrenal function or the introduction of adrenocorticotropic hormone from the outside, is a natural character.On the property of thymic hypoplasia subjected under the influence of adrenocorticotropic hormone based testing method of this hormone.
adrenal mechanism of involution of the thymus gland in times of emergency stimuli, apparently, occurs in most cases, but does not exclude the possibility of an involution of the direct action on the gland of some agents (X-ray irradiation, embihin and its derivatives, pyridoxine poor diet).The physiological significance of these changes in the thymus gland effects on the body emergency stimuli has long been quite outstanding.As has been observed, the changes occurring in the thymus gland in response to "stress" or administering the hormones of the adrenal cortex, are complex: the destruction of the lymphoid cells of the thymus results in a temporary release from contact with them, which activates the cells of the epithelial base to the proliferative and secretoryactivity inhibited in normal conditions.Active secretory beginning produced hypertrophied epithelial cells and gassalevymi calves, affect the adrenal cortex.The effect of this action is similar to that of adrenocorticotropic hormone, t. E., They activate the synthesis and excretion into the blood hormones of the adrenal cortex.Apparently, the thymus gland in growing animals is the body in some way complement kortikotropnuyu function of the anterior pituitary.Regarding
lymphocytes decay products, they are likely to enter the blood in a free form or previously captured hypertrophic thymic epithelial cells;last migrate to the lymph nodes where enter the blood.The literature suggests that the decay products of thymic lymphocytes play an important role in the stimulation of the phagocytic activity of cells and immune responses.The thymus gland - the main body of acquired immunity.All immunologically competent cells of a mammal are formed in the thymus, where they migrate further in different organs and tissues.Lymphoid cells of the thymus gland are able to produce clones that produce different kinds of antibodies.
Apparently, thymus, being responsible for the differentiation of lymphoid cells on specific immunological functions, may serve as one of important neurohormonal factors influencing the reactivity and involved in the development of autoimmunity.
experimentally established that removal of growing animals even one adrenal gland prevents age involution of the thymus gland.These changes are caused by loss of the thymus adrenal corticoids, hormones and not the brain substance.This position is confirmed by the fact that the hyperplasia-Rowan thymus undergoes involution only under the influence of adrenal hormones, adrenaline and noradrenaline and similar effects do not possess.Insufficiency of the adrenal corticoids function is, obviously, the reason is often observed hyperplasia of the thymus and lymphoid organs with Addison's disease.So out of 15 adult patients who died of Addison's disease, in 7 sections on persistent thymus gland was detected, and the more or less pronounced hyperplasia lymphoid organs was observed in all cases.
It is generally recognized that castration before puberty delay in humans and animals age involution of the thymus gland.On the contrary, the introduction of hormones of sex glands, as well as gonadotropin, it is possible to cause atrophy of the thymus gland.As for the reverse influence of the thymus gland in the sexual glands, the issue has not been studied, and the results are inconsistent.According to some researchers, thymectomy in animals who have not reached puberty, leading to the rapid development of the sex glands and the awakening of the sexual instinct;others on the contrary, in these conditions observed inhibition activity of the gonads.Perhaps the inconsistency of the results depends on the fact that the registration of the consequences of thymectomy in relation to the sex glands was carried out in very different terms after the extirpation of the thymus gland.Experience has shown that guinea pigs immediately after thymectomy is a rapid development of the gonads, and later comes their degeneration and atrophy.
Prolonged administration of high doses of thymus extracts is in growing animals delayed puberty.These experiments indicate a close correlative links between the thymus gland and the gonads.Probably, the thymus gland has an inhibiting effect on sexual development in pre-adolescent.
Clinicians have long paid attention to the fact that patients with hyperthyroidism, especially in the absence of severe cachexia, there is hyperplasia of the lymphoid organs and the thymus gland.These observations give reason to believe that thyroid hormones stimulate the lymphoid tissue of the thymus gland.In experiments in mice, it was found that thyroid extracts induce stimulation of the lymphoid tissue in general and in particular the thymus.On the contrary, the introduction of chickens antithyroid agents (thiouracil, Sulfidine) leads to a drastic reduction in the weight of the thymus by the cellular elements of the cortex.The stimulating effect of thyroid hormones on the thymus particularly evident until puberty, is not affected by the inhibitory effect on the thymus hormones sex glands.The mechanism of the effect of the thyroid gland in the thymus is not entirely clear.Perhaps here there is not direct, but mediated by the adrenal cortex action of thyroid hormones.Excess thyroid hormone inhibits the function of the adrenal cortex, which is accompanied by hyperplasia of the lymphoid tissues of the thymus and lymphoid organs.This assumption is consistent with the clinical observations.Thus, patients with hyperthyroidism, in which, as mentioned above, is often observed thymus hyperplasia, detected failure of adrenocortical function.Observations concerning the reverse effect on the thyroid gland of the thymus, is extremely contradictory and unconvincing.
Since thymus extracts reduce kaltsiemiyu and parathyroid hormone increases it, there was a look in the literature about the presence of antagonistic relationship between the thymus and parathyroid glands.In connection with the thymus gland calcium metabolism and indicates the fact that the administration of calcium slows involution of the thymus gland in response to emergency stimuli.
Among clinicians there was a view that some people have multiple bone lesions, combined with a violation of the general nutrition, have similarities with the consequences of thymectomy in animals and, apparently, due to the thymus gland insufficiency.The panel in such cases are often found hypoplasia of the thymus gland, even in children, as evidence of the pathogenetic role of hypofunction of the thymus gland in the development of pain.However, many attempts to treat multiple bone lesions thymus preparations have ended in failure.Apparently, when these sufferings hypoplasia of the thymus gland is not the cause but the consequence of the disease.
relationship thymus and pancreas are not well understood.After thymectomy an increase in the islets of Langerhans in the pancreas in laboratory animals.Some researchers have observed when administered to an animal lipid extract thymus opposite effect of insulin action: reduction of glycogen in the liver and increasing the amount of blood sugar.
Many authors have attempted to examine the relationship of the thymus with vitamin metabolism.It can now be regarded as established the effect of vitamin B6 (pyridoxine), on the thymus.A diet devoid of pyridoxine, is an involution gland.
in the literature for a long time drawn attention to the connection of the thymus with the processes of hematopoiesis.Some authors believe that participation in hematopoiesis is the only function of the thymus gland.thymus extracts guinea pigs cause increase in the percentage of lymphocytes in the peripheral blood, leading to thymectomy and reduction of lymphocytes in the blood, lymph nodes and spleen.There was a decrease in the percentage of lymphocytes in the blood of pigs thymectomy.Hoods made from the spleen and lymph nodes, in contrast to the thymus extracts have no effect on peripheral blood lymphocyte counts of mice.These experiments served as a basis to believe that the thymus has a specific effect on lymphocytes.It is assumed that the stimulating factor lymphocytopoiesis, produced by epithelial structures of the thymus gland.
- Diseases of the thymus (thymus) gland
- Physiology of the adrenal cortex
- Syndrome Cushing - Cushing
- diagnosis and course of the syndrome Cushing's
- Treatment syndrome Cushing's
- androgen-producingtumors of the adrenal cortex
- Biological effects of catecholamines
- diagnosis and treatment of pheochromocytomas
- Diseases of the adrenal medulla
- treatment of chronic adrenal insufficiency
- congenital (inborn) hyperaldosteronism
- congenital virilizing adrenal hyperplasia
- treatment of congenital adrenal hyperplasia
- Acute failure of the adrenal cortex
experimental data on the influence of the thymus gland in the maintenance of blood lymphocytes consistent with clinical observations.The presence of lymphocytosis in children, when the thymus gland has the highest functional activity and hyperplasia cancer or the introduction of its extracts in adults suggests the involvement of the thymus gland, along with other endocrine glands in the redistribution of blood cells and, possibly, in the stimulation lymphocytopoiesis.Some researchers see the age involution of the thymus gland one of the reasons for the disappearance of lymphocytosis in adults.
The literature drew attention to the role of primary dysfunction of the thymus gland in the pathogenesis of lymphocytic leukemia.The latest foreign studies devoted to this issue suggests that limfopoetichesky factor contained in the thymus, in its effect on lymphocytopoiesis identical to blood plasma of patients with leukemia.This assumption is based on the fact that the thymectomy in vysokoleykoznyh strains of mice dramatically reduced the incidence of spontaneous and induced by carcinogens, and x-rays leukemia.In contrast, transplantation of pieces of thymus of mice strains normal leukemic increases their incidence of leukemia.Obviously, the thymus is of some importance in the development of leukemia in animals, in particular mice, in which it undergoes slow age involution.Increase of thymus lymphocytic leukemia in patients in particular in acute lymphatic leukemia in children, is often observed, but it was not due to hyperplasia of epithelial cells and cells gassalevyh, which is attributed to the secretion factor lymph poetry and infiltration of lymphoid organ.The process is identical to the infiltration of other non-lymphoid organs observed in systemic blood suffering.We can not therefore be considered proved pathogenetic role of the thymus in the development of lymphocytic leukemia.
This role of the thymus gland is not excluded under status thymicolymphaticus and myastenia gravis.
19 Apr, 2016
19 Apr, 2016