[The compensatory-adaptive reactions of the thyroid and adrenal adrenergic structures in the postnatal ontogeny of sympathectomized rats]. / Kompensatorno-adaptatsionnye reaktsii adrenergicheskikh struktur shchitovidnoi zhelezy i nadpochechnikov v postnatal'nom ontogeneze desimpatizirovannykh krys.

The study was performed in albino rats treated during first two postnatal weeks with guanetidin isotonic solution injected subcutaneously in dose 20 mg/kg body weight to obtain desympathization. Control animals received similar volume of the solution during equal terms. Thyroid and adrenal glands were studied in 1- and 6-month-old rats both by light and electron microscopes. Serotonin and catecholamines were revealed by fluorescent-histochemical method. In experimental 1-month-old animals morphological indexes indicate the thyroid gland hyperfunction. In these animals serotonin and catecholamines content is lower in parafollicular endocrinocytes, mast cells and in adrenergic fibres, the density of which is significantly lower than that in control animals. The adrenal gland weight in experimental animals increases due to the medulla. Serotonin and catecholamine content is essentially higher. Thyroid gland in 6-month-old experimental rats is hyperfunctioning. Adrenal fibres density in its stroma is close to control indexes. Catecholamines and serotonin adrenal glands medulla grows with age and remains higher than the appropriate control level, which indicates active participation of adrenal glands in adaptive reactions is desympathized animals. Serotonin plays an important role in local regulation of thyroid glands. Parafollicular endocrinocytes perform the function of local biogenic amines-producers, while mast cells regulate the serotonin content.

[Effects of dosed sympathectomy on the development of adaptation-compensation reaction of C-cells of the thyroid gland and chromaffin cells of the adrenal glands in young rats]. / Vliianie dozirovannoi desimpatizatsii na razvitie adaptatsionno-kompensatornykh reaktsii C-kletochnogo apparata shchitovidnoi zhelezy i khromaffinotsitov nadpochechnikov u krys rannego vozrasta.

Using radioimmunological, morphometrical, electron microscopic and luminescent methods, comparative analysis of thyroid C-cells and adrenal chromaffin cells has been carried out at guanethidine sympathectomy in young rats. Significant decrease of functional activity of C-cells with concomitant hyperplasia of C-cells population under blockade of sympathetic influences has been revealed. Compared to C-cells, adrenal chromaffinocytes of sympathectomized rats possess higher degree of structural-functional mobilization and are characterized by intensive secretion of catecholamines directed at restoration of tissue neurotransmitter deficit.

[Dynamics of postnatal histogenesis of the thyroid in normal rats and after sympathectomy]. / Dinamika postnatal'nogo gistogeneza shchitovidnoi zhelezy krys v norme i pri desimpatizatsii.

The changes of the thyroid gland and neurocytes of the cranial sympathetic ganglia were followed in rats of different ages after guanethidine injections with the use of radioimmunological assay, electron microscopy and morphometry. The injection of 15 mg of the drug per kg of body weight within the first two weeks after birth caused the death of over 80% of the cells in the sympathetic ganglion. In the sympathectomized 15-day- and 1-month-old rats the functional activity of the thyroid gland was markedly reduced. Later on, intrathyroid hormonogenesis somewhat increases due, apparently, to partial recovery of the organ adrenergic innervation and increase in the production of thyrotropic hypophysial hormone and calcitonin.

[Characteristics of the compensatory repair processes in the thyroid of 1-month-old rats as affected by sympathectomy]. / Kharakteristika kompensatorno-vosstanovitel'nykh protsessov shchitovidnoi zhelezy odnomesiachnykh krys v usloviiakh desimpatizatsii.

A considerable decrease in the amount of sympathetic nervous cells in neonatal rats injected guanethidine resulted in the depression of thyroid gland functional activity in 1-month-old animals, there was an apparent parallel increase in the proliferative activity of the gland. A 2/3 thyroidectomy led to the functional tension of the remaining part of the organ. A comparison of compensatory-reparative processes after thyroidectomy has shown similarity of reparative changes in experimental and control rats, however, the degree of repair potential was much higher in the sympathectomized thyroid gland.

[Morphofunctional characteristics of the thyroid gland in intact and partially sympathectomized rats of different age groups]. / Morfofunktsional'naia kharakteristika shchitovidnoi zhelezy intaktnykh i chastichno desimpatizirovannykh krys raznykh vozrastnykh grupp.

The morphological and functional age-dependent changes have been studied in the thyroid gland of infantile (1-month-old), immature (2- and 3-month-old) and sexually mature (6-month-old) male rats. The decrease in thyroid functional activity with ageing was proved. Chemical sympathectomy (guanethidine at a dose of 15 mg/kg intramuscularly for 14 days after birth) was accompanied not only by morphological reconstruction of the thyroid tissue, but also (especially in 1-month-old rats) by a delay in transport-organic phase of iodine metabolism and a decline in thyroid hormone serum level. Later on, the compensatory hormonogenesis reinforcement occurs as a result of partial adrenergic innervation recovery.

[Effect of different fixation methods and partial chemical sympathetic denervation on cell size and 3H-leucine incorporation by rat sympathetic neurocytes]. / Vliianie razlichnykh sposobov fiksatsii i chastichnoi khimicheskoi desimpatizatsii na razmery kletok i vkliuchenie 3H-leitsina simpaticheskimi nevrotsitami krys.

Dimensions of sympathetic nerve cells and of their nuclei were studied using various methods of fixation and embedding media, as well as autoradiographic indices of the protein synthesized system of neurocytes in normal rats, and in rats partially sympathectomized at an early age. On the ground of different changes in the average size of neurocytes seen under various methods of fixation, and of decreased labeling intensity of large neurocytes after the injection of the labeled protein biosynthesis precursor there is some reason to believe that large neurocytes may appear in the late reproductive age mainly due to the nerve cell cytoplasm swelling as a consequence of exhaustion of their growth resources.

[Autoradiographic and electron-microscopic analysis of sympathetic neurocytes in rats of different ages after partial chemical sympathectomy]. / Radioavtograficheskii i élektronno-mikroskopicheskii analiz simpaticheskikh nevrotsitov posle chastichnoi khimicheskoi desimpatizatsii krys raznogo vozrasta.

Neurocytes of the cranial cervical sympathetic ganglion have been studied in normally developing and partly guanidine-desympathized rats at 1 and 12 months of age. In ganglia of the both age groups less than 20% of the cells are preserved. But the somatic development of the animals does not change, and an average volume of the neural cells in the experiment exceeds that of the control. At the age of 1 month in the experimental rats the incorporation of the protein biosynthesis labelled precursor in the neural cells increases, as does its amount evacuated into the terminals at a slow rate. Together with some ultrastructural rearrangements in the perikaryons it could demonstrate certain hyperplastic processes that are possibly directed towards an increased adrenergic innervation in the periphery at the expense of growing processes. Age changes in all the rats occur similarly, nevertheless, certain acceleration of the age dynamics is observed in the partly desympathized animals.

[Morphophysiologic changes in the thyroid gland following exposure to retabolyl]. / Morfofiziologicheskie izmeneniia shchitovidnoi zhelezy pri vozdeistvii retabolila.

Morphofunctional rearrangement of the thyroid gland resulted from retabolile effect has been studied in 25 tortoises (Testudo horsfieldi) and in 30 white rats. The changes observed evidence in favour of activation of all secretory phases in thyroid hormones. At an overstrained hormonal stress in the thyroid gland, hypofunction of the organ is the initial state in the tortoise, while in the white rat an increased physiological wearing out in thyroid cells and their destruction are noted. Therefore, the relation between proliferation and destruction of thyrocytes is shifted towards the latter.

[Effect of lithium chloride on the thyroid gland of white rats]. / Vliianie khlorida litiia na shchitovidnuiu zhelezu belykh krys.

The morphological and functional changes in the thyroid tissue of white rats injected lithium chloride at doses 0.5 mekv/kg and 1.0 mekv/kg (groups 1 and 2, respectively) during three weeks were studied by the radiometric, histological and biochemical methods. The radiometric, histological and biochemical methods. The inhibitory action of lithium chloride on hormonogenesis in the thyroid gland and secretion of thyroid hormones into the blood was proved to be directly related to the lithium dose and concentration in the blood. The data of intravital radiometric and morphological analysis of the organs of the 1st group animals suggest some activization of the gland function, with the secretion of the hormones into the blood being suppressed. Increased concentration of the drug inhibits hormonogenesis and secretion of thyroid hormones into the blood.