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Biomedical subjects

L A Us

Publications and source records attributed to L A Us.

5 recordsLinked to original sources
PubMed1985

Effect of thymus on the thyroid and pituitary thyrotropic function.

Thymus inflammation induced in infantile guinea pigs and rabbits by administration of melted paraffin drops into the thymic parenchyma resulted in enhancement of the thyroid functional activity. Thymosin injections provoked an identical effect. In both variants of these experiments the pituitary thyrotropin level remained within the norm. Hence, the pituitary thyrotropic function as in thyrotoxicosis lost the ability of response to enhancement of the thyroid hormone production. This result suggests that the cause of disorganization of the negative feedback between the thyroid and the pituitary thyrotropic function might be attributed to enforcement of the stimulated thymus secretory activity.

Animals↗
PubMed1983

[Parafollicular cells in the regenerating thyroid gland].

Ten days after partial thyroidectomy (excision of the lower half of the thyroid left lobe) made in mature male rabbits, functional activity of thyrocytes markedly rose. That was the organism compensatory reaction to the decreased thyroid hormone production due to the enhancement of the pituitary thyrotropin secretion. However, parafollicular cells detected by the Sawicki method underwent reduction in the number and size, which was fairly appreciable in the regenerating thyroid lobe and insignificant in the lobe left intact. This reduction is probably caused by the fact that secretory activity of parafollicular cells is stimulated by sympathetic impulses, whereas in the regenerating thyroid, there prevail the parasympathetic effects.

Animals↗
PubMed1981

[Effect of sympathetic impulses on parafollicular cells (K-cells) of the thyroid gland].

Reaction of K-cells (detectable by the Savitsky method) to stimulation of the superior cervical sympathetic ganglia or to their removal was examined in experiments on male rabbits. Stimulation of the sympathetic ganglia attained as a result of application to them of a ringlet made of solid silver wire produced a marked rise of the number and size of K-cells, with the serotonin content in the thyroid gland being significantly increased as compared to the initial level. Bilateral cervical sympathectomy entailed a reduction in the serotonin content and in the size of K-cells. In the course of hyperthyroidization the functional activity of the thyroid epithelium decreased and K-cells underwent a pronounced reduction.

Animals↗
PubMed1976

[Catecholamine concentration in the hypothalamus following alteration of pituitary adrenocorticotropic function].

Norepinephrine, epinephrine and serotonin levels were studied in male rabbit hypothalamus and midbrain under the influence of different factors potentiating the hypophysial adrenocorticotropic function. Intensification of this adrenohypophysial function was accompanied by a certain decrease in the hypothalamic and midbrain norepinephrine level and by the appearance of epinephrine normally absent here. The role of serotonin in the regulation of the investigated pituitary function was not revealed since potentiation of this function was observed both with the lowered and with the elevated concentrations of this monoamine in the hypothalamus.

Adrenocorticotropic Hormone↗