thymic-factor--circulating and Hypothyroidism

Changes of the immune system state were investigated in mice after performance of thyroidectomy under the influence of hormonal therapy using thyroxin and immunotropic preparations thymogen and polyoxydonium. In hypothyrosis there was observed the trustworthy lowering of the thymus endocrine function, interleukine-2 activity, cytotoxic activity in the physiological cell-killers, the leukocytes proliferating ability and increase of the blood content of circulating immune complexes as well. The restorational therapy conduction using thyroxin, injections of thymogen or polyoxydonium removed the above mentioned changes only in part. The immunomodulators application, under condition of the hypothyrosis compensation occurrence, have had promoted the essential raising of their therapeutic action and secured the immune state restoration after thyroidectomy performance.

Topics: Animals; Cytokines; Hypothyroidism; Immunologic Factors; Male; Mice; Mice, Inbred CBA; Thymic Factor, Circulating

An Endocrine function of the thymus was studied by analyzing the level of thymulin in rats in 1-6 months after extirpation of the thymus. The level of thymulin in rats after thyroidectomy has been shown to be reduced maximally in 6 months after an operation. An inhibitor of thymulin was detected in the blood serum in a month after extirpation, then it disappeared completely from it. After thyroidectomy the mass of animals decreased, as well as an absolute and relative mass of the thymus and its cellular content. Thyroidectomy was followed with a marked decrease in the thyroid hormones content in the blood serum and a reduce in the adrenal cortex, especially at a distant period following an operation. The data obtained evidence that it is sensible to use the agents of the thymic origin to restore the hormone balance at hypothyroidism, together with the substitute therapy.

Topics: Animals; Body Weight; Disease Models, Animal; Hypothyroidism; Male; Organ Size; Rats; Thymic Factor, Circulating; Thymus Gland; Thyroid Hormones; Thyroidectomy

Topics: Acromegaly; Adolescent; Adult; Child; Diabetes Mellitus, Type 1; Endocrine System Diseases; Growth Hormone; Humans; Hyperthyroidism; Hypothyroidism; Male; Pituitary Neoplasms; Prolactinoma; Thymic Factor, Circulating; Thymus Gland; Zinc

Several in vivo experimental and clinical studies suggest that the production of thymic hormones, such as thymulin (Zn-FTS), is modulated by thyroid hormones. It was not determined in these studies, however whether such modulation is exerted directly on the thymic epithelial cells which synthesize and secrete thymic hormones. In order to discriminate between direct and indirect modulation, the effect of thyroid hormones on the in vitro production of thymulin by whole thymic organ culture, as detected by the rosette inhibition assay, has been investigated. Donors of thymuses were young 6N-propyl-2 thiouracil (PTU)-treated hypothyroid Balb/c mice and normal littermates. Thymuses from hypothyroid mice were shown to produce concentrations in vitro nearly undetectable of thymic hormone, when compared to thymuses from normal mice. The in vitro addition of triiodothyronine (T3) caused a complete recovery of the thymic hormone production by thymuses from hypothyroid mice and an increased synthesis even by normal thymuses over control values. The complete blockade of in vitro thymic hormone production with cycloheximide, which inhibits mRNA and protein synthesis but not thyroid hormone permissive actions, suggests that the T3 induced increment of thymic hormone level in the supernatant is due to de novo synthesis. Furthermore, the number of thymulin-producing cells, as detected by immunofluorescence using a specific antithymulin monoclonal antibody, which is quite low in thymuses from hypothyroid mice, is completely regained after in vitro incubation with T3. These findings support the idea that the modulation of thyroid hormones on thymic endocrine activity is directly exerted at thymic level.

Topics: Animals; Cycloheximide; Fluorescent Antibody Technique; Hypothyroidism; Kinetics; Male; Mice; Mice, Inbred BALB C; Organ Culture Techniques; Propylthiouracil; Thymic Factor, Circulating; Thymus Gland; Thymus Hormones; Triiodothyronine

A good body of experimental and clinical evidences suggests that bidirectional interactions do exist between the neuroendocrine system and the thymus activity. In particular, thymic endocrine activity seems to be strongly influenced by neuroendocrine signals. In this context, studies performed in hyper- and hypothyroid subjects and in the low triiodothyronine (T3) syndrome, which affects premature infants, have clearly shown that thyroid hormones and in particular T3 physiologically modulate thymic peptide secretion. In vitro experiments, with thymic whole-organ cultures, have demonstrated that thyroid hormones exert their action on the epithelial cells of the thymus deputed to synthesize and secrete thymic peptides and that such an effect does not seem to depend on the known permissive action of thyroid hormones.

Topics: Adolescent; Adult; Aged; Aging; Female; Humans; Hyperthyroidism; Hypothyroidism; Infant, Newborn; Male; Middle Aged; Thymic Factor, Circulating; Thymus Gland; Thyroid Gland; Thyroid Hormones

The thymus produces humoral factors that induce proliferation and differentiation of T-cells, which are responsible for cell-mediated immunity. Recent data in animals suggest that such thymic hormone activity is modulated by the neuroendocrine network and, in particular, by thyroid hormones, but no information is presently available in humans. To study this question, we measured the circulating thymic factor called thymulin (Zn-FTS) in hyperthyroid and hypothyroid patients. Thymulin levels were higher in hyperthyroid patients than in normal subjects, whereas hypothyroid patients had lower thymulin levels than normal subjects. A significant correlation was found between circulating thymulin and serum T4 and T3 levels. Thymulin changes could be reversed by appropriate treatment in both groups of patients. Recent data indicate that zinc is required to confer biological activity on thymic hormone molecules. This raised the question of whether the influence of thyroid status on thymulin activity could be mediated by changes in serum zinc concentrations. No support for such an explanation was obtained by thymulin measurements by a modified bioassay using an optimal zinc concentration in the assay system. In conclusion, thyroid status modulates thymic endocrine function in humans. Whether and to what extent such modulation is relevant to the function of the immune system remain to be established.

Topics: Adolescent; Adult; Aged; Female; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Rosette Formation; Thymic Factor, Circulating; Thymus Gland; Thymus Hormones; Thyroid Gland; Thyroxine; Triiodothyronine