Effect of Prolonged TSH Suppression on Cardiovascular System / 대한갑상선학회지

Prolonged thyroid-stimulating hormone (TSH) suppression caused by exogenous subclinical thyrotoxicosis has been reported to impose harmful effects on cardiovascular system. Those effects involve increase in heart rate and myocardial mass, impaired ventricular diastolic and systolic function, decreased exercise capacity, decreased arterial elasticity, development of atrial tachyarrhythmia, and increase in cardiovascular adverse events. Tailored dose adjustment of thyroid hormone under the guidance of TSH level for obviating oversuppression of TSH, and use of beta blockers can reduce cardiovascular adverse effects in patients who undergo thyroid hormone therapy.

Long-Term Effect of Prolonged TSH Suppression on the Skeletal System / 대한갑상선학회지

Thyroid hormone (TH) has a pivotal role in skeletal development, linear growth and maintenance of adult bone mass. Additionally, there are several studies which supported the direct effect of thyroid-stimulating hormone (TSH) on bone metabolism. As thyroid disease is one of the most common endocrine problems, the clinical impact of thyroid dysfunction on bone metabolism has been elucidated in various studies. Hyperthyroidism is associated with excessive loss of bone mass and an increased life-time risk for fractures. Adverse effects of hyperthyroidism in bone metabolism are distinct in postmenopausal women. Subclinical hyperthyroidism may also affect bone mineral density, however, its effect on fracture rate remains to be established. The effect of exogenous TH on bone tissue is somewhat controversial. Patients with hypothyroidism or differentiated thyroid carcinoma showing suppressed TSH caused by excessive TH replacement, especially postmenopausal women, appear to have lower bone mineral density and higher incidence of fractures than euthyroid subjects without exogenous TH. On the contrary, patients who are on exogenous TH with a normal range of TSH seem to have similar bone mineral density and fracture rates as euthyroid subjects. As most patients with differentiated thyroid carcinoma are taking exogenous thyroid hormone to suppress TSH, individual risks of both fracture and recurrence of carcinoma should be evaluated during the follow-up period of those patients. In general, in the management of thyroid disease, it should be taken into account that most thyroid dysfunction may result in reduced bone density and an increased fracture rate.

Ultrastructural characterization of the pars distalis of the Indian female Sheath-tailed bat, Taphozous longimanus (Hardwicke) / Caracterización ultraestructural de la pars distalis del murciélago cola de vaina hembra indio, Taphozous longimanus (Hardwicke)

The present ultrastructural observations demonstrate the presence of six cell types in the pars distalis of non-pregnant and pregnant bats of Taphozous longimanus. In the pars distalis of T. longimanus, STH cells are round to oval with eccentrically placed nucleus, numerous secretory granules and well developed Golgi indicate a cell under vigorous synthetic activity while those filled with secretory granules with reduced Golgi complex suggest reserve or storage state of cells. LTH cell is characterized by the large secretory granules, dilated endoplasmic reticulum and numerous mitochondria in the cytoplasm which indicate that these cells are hypertrophied and synthetically very active during pregnancy. ACTH cells are found either singly or in groups and are elongated or angular with long cytoplasmic processes. The size and peripheral arrangement of secretory granules are characteristic of ACTH cell. TSH cells are distributed mostly towards the periphery of the pars distalis of T. longimanus. They are elongated, polygonal or triangular in shape. The secretory granules are small, electron dense, 150-200 nm in diameter. The rough endoplasmic reticulum is very well developed. In FSH, the secretory granules are small (200 to 400 nm) and less in number and are distributed towards the periphery of the cell. FSH cells show well developed mitochondria, Golgi and rough endoplasmic reticulum indicating active state of FSH during estrus and pregnancy. The hypertrophy of FSH and LH cells during pregnancy is associated with filigreed cytoplasmic pattern giving a bizarre appearance. At late pregnancy, FSH and LH cells are highly active and synthesize large quantities of hormone as indicated by the development of cell organelles.

Las observaciones ultraestructurales actuales demuestran la presencia de seis tipos de células en la pars distalis de murciélagos Taphozous longimanus preñadas y no preñadas. En la pars distalis del T. longimanus, las células STH son redondas u ovaladas con un núcleo excéntrico, numerosos gránulos de secreción y un Golgi bien desarrollado que indican una célula en actividad de síntesis vigorosa, mientras que las llenas de gránulos de secreción con un complejo de Golgi reducido sugieren un estado celular de reserva o almacenamiento. Las células LTH se caracterizan por grandes gránulos de secreción, el retículo endoplásmico dilatado y numerosas mitocondrias en el citoplasma, indicando que estas células están hipertrofiadas y con una actividad sintética muy activa durante el embarazo. Células de ACTH se encuentran de forma individual o en grupos, son alargadas o angulares, con largos procesos citoplásmicos. El tamaño y la disposición periférica de los gránulos de secreción de ACTH son característicos de la célula. Células de TSH se distribuyen principalmente hacia la periferia de la pars distalis del T. longimanus. Ellos son alargadas, poligonales o de forma triangular. Los gránulos de secreción son pequeños, electrodensos, de 150-200 nm de diámetro. El retículo endoplasmático rugoso está muy bien desarrollado. En células FSH, los gránulos de secreción son pequeños (200 a 400 nm), menores en número y se distribuyen hacia la periferia de la célula. Células FSH muestran mitocondrias bien desarrolladas, Golgi y retículo endoplasmático rugoso que indica el estado activo de la FSH durante el estro y la preñez. La hipertrofia de las células de FSH y LH durante la preñez se asocia con un patrón citoplasmático filigrana dando una extraña apariencia. Al final de la preñez, las células de FSH y LH son muy activas y sintetizan grandes cantidades de hormonas, como producto del desarrollo de las organelos celulares.

Tumores hipofisários secretores de TSH: relato de dois casos e revisão da literatura / TSH-secreting pituitary tumors: two case reports and literature review

INTRODUÇÃO: Tumores hipofisários secretores de hormônio estimulante da tireoide (TSH), tireotropinomas, são raros e correspondem a menos de 2 por cento de todos os adenomas da hipófise. Manifestam-se clinicamente com sintomas e sinais de tireotoxicose, eventualmente associados a sintomas compressivos, sobretudo visuais, devido ao efeito de massa do tumor. Esses tumores se caracterizam pela presença de níveis séricos elevados de hormônios tireoidianos e níveis séricos elevados, ou inapropriadamente normais, de TSH. Frequentemente, ao diagnóstico, há relato de tratamento prévio cirúrgico, medicamentoso e/ou ablativo, por hipótese de hipertireoidismo primário por doença de Graves. OBJETIVO: Relatar dois casos de tireotropinomas acompanhados na Unidade de Neuroendocrinologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP) e revisar a literatura visando ao manejo desta afecção. CONCLUSÃO: Na presença de hormônios tireoidianos elevados e níveis de TSH inapropriadamente normais ou elevados, a possibilidade de adenoma hipofisário produtor de TSH deve ser considerada com vistas à realização da terapia adequada.

INTRODUCTION: TSH-secreting pituitary adenomas are rare pituitary functioning tumors accounting for less than 2 percent of the pituitary adenomas. The clinical feature consists of thyrotoxicosis occasionally associated to tumoral symptoms due to mass effect. The biochemical feature consists of elevated thyroid hormones levels and normal or high TSH concentrations. This disease is often wrongly diagnosed as Grave's disease, and the ablative therapy is frequently conducted prior to the diagnosis. OBJECTIVE: To report two cases followed in the Neuroendocrine Unit of Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo and to review the literature aiming at the management of this affection. CONCLUSION: In the presence of elevated thyroid hormone levels associated with inappropriate normal or increased TSH levels, the possibility of a TSH-secreting pituitary adenoma should be considered for the proper medical treatment.

Alterations in TSH and thyroid hormones following mobile phone use

In recent years, the widespread use of mobile phones has lead to a public debate about possible detrimental effects on human health. In spite of years of research, there is still a great controversy regarding the possibility of induction of any significant physiological effects in humans by microwave radiations emitted by mobile phones. This study aims to investigate the effects of electromagnetic fields induced by the Global System for Mobile communications [GSM] mobile phones on the Thyroid Stimulating Hormone [TSH] and thyroid hormones in humans. 77 healthy university students participated in this study. The levels of T3, T4 and TSH were measured by using appropriate enzyme-linked immunosorbent assay [ELISA] kits [Human, Germany]. The average levels of T3,T4 and TSH in students who moderately used mobile phones were 1.25 +/- 0.27 ng/ ml, 7.76 +/- 1.73 micro g/dl and 4.25 +/- 2.12 micro u/l respectively. The levels in the students who severely used mobile phones were 1.18 +/- 0.30, 7.75 +/- 1.14 and 3.75 +/- 2.05 respectively. In non-users, the levels were 1.15 +/- 0.27, 8.42 +/- 2.72 and 2.70 +/- 1.75, respectively. The difference among the levels of TSH in these 3 groups was statistically significant [P<0.05]. As far as the study is concerned, this is the first human study to assess the association between mobile phone use and alterations in the levels of TSH and thyroid hormones. Based on the findings, a higher than normal TSH level, low mean T4 and normal T3 concentrations in mobile users were observed. It seems that minor degrees of thyroid dysfunction with a compensatory rise in TSH may occur following excessive use of mobile phones. It may be concluded that possible deleterious effects of mobile microwaves on hypothalamic-pituitary-thyroid axis affects the levels of these hormones

A case of TSH-secreting pituitary adenoma with acromegaly / 대한내과학회지

Growth hormone (GH) and thyrotropin (TSH)-secreting pituitary adenomas are very rare and account for only 0.5% of all pituitary adenomas. We report a case of a GH/TSH-secreting pituitary adenoma in a 53-year-old male patient. He presented with symptoms of thyrotoxicosis, clinical features of acromegaly, and diabetes mellitus. The laboratory examinations showed high serum levels of free T4, TSH, and free alpha-subunit. Additionally, serum levels of GH and insulin-like growth factor (IGF-1) wereincreased. GH was not suppressed below 1 microgram/L by an oral 75 g glucose loading test, and TSH was not stimulated by thyrotropin- releasing hormone. A sellar MRI showed a large lobulated mass on the pituitary gland, so transcranial surgery was performed. Immunohistochemical staining showed anti-GH and anti-TSH positive tumor cells in the cytoplasm. Serum GH, IGF-1, free T4, and TSH levels normalized after surgery.

Effect of non detectable thyroid stimulating hormone [TSH] levels on thyroid activity

Thyroid hormones, triiodothyronine [T3] and thyroxin [T4], affect almost all metabolic activities of tissues and are produced under influence of the anterior pituitary hormone, the thyroid stimulating hormone [TSH], which stimulates secretion of thyroid hormones, and is itself under the control of the hypothalamic thyroid releasing hormone [TRH]. The present study was conducted to observe the effect of non-detectable levels of TSH on thyroid hormones, on the basis of gender and age. Analysis of data through student's 't'-test revealed that prevalence of thyroid disorders in the studied group was more among females. However, the disorders were not age dependent. Most common condition associated with non-detectable TSH levels was hyperactivity of the thyroid gland, followed by sub-clinical hyperthyroidism

The Effect of reconstituted basement membrane on the expression of the anterior pituitary hormones of the rat / 대한해부학회지

This study was performed to investigate the effect of Matrigel, a reconstituted basement membrane, on the expression of the anterior pituitary hormones in culture. Rat pituitary cells cultured for 6 days on Matrigel showed 3-dimensional, lobular structures with connecting cells while those on plastic showed flat, polygonal cells forming a monolayer. Western blot analysis showed that prolactin (PRL) content in the anterior pituitary cells was higher compared to those cultured on plastic. In comparison, TSH expression was not increased in cultures on Matrigel. The total cell number and the proportion of fibroblasts was decreased. These results suggested that Matrigel is a useful culture substrate for the enhanced expression of PRL but not for TSH. Further studies are needed in order to find a useful culture substrate for TSH cells.

An Experimental Studies of the Influence of Various Hormones on the Wound Repair Process / 대한피부과학회지

Conflicting results have been reported, as to whether or not wound repair is influenced following treatment with low doses of prednisolone, insulin, or thyrotrophic hormone. The present studies were undertaken to evaluate and compare the influence of above hormones on the wound repair process and their target organs in rats at different times after operation. The influence of the above hormones were observed as measurement of the tensile strength of healing skin incisions and the histologic finding of the wound sites and the target organs staining with H-E, PAS, and Masson's trichrome method. Saline 0. 1 ml were injected daily intramusculary in control group: prednisolone acetate 0. 2ml (4mg/kg/day) in prednisolone treated group: regular zinc insulin 0.1 ml(1.5IU/kg/day) in insulin treated group; thyrotrophin 0.1 ml (0.4IU/kg/day) in TSH trcated group. The observation period wer at 4th day, 7th day, 14th day and 21st day of post-operation. The results were as follows: 1. Prednisolone treated group: (1) The tensile strength were decreased at 4th and 7th day than control groups, but there were no statistically significant difference at 14th and 21st day from control group. (2) In histologic findings of the wound sites at 4th and 7th day, the repair processes were suppressed, but at 14th and 21st day, there were no difference from control group. (3) In histologic finding of adrenal cortex, the atrophic changes was observed from early stage. 2. Insulin treated group: (1) There were no statistical difference from control group in tensile strength at each observation period. (2) In histologic findings of the wound sites, the pictures of the repair processes were similar with control group at each observation period. (3) Atrophic change of islets of Langerhans in pancreas was observed at each observation period. 3. TSH treated group: (1) The tensile strength were increased at 4th, 7th, and 14th day than control group, but there was no statistical difference at 21st day frorn control group. (2) In histologic findings of the wound sites, the repair processes were aecelerated at 4th and 7th day than control group, but there were no defferences at 14th and 21st day from control group. (3) Hyperplastic change of acini in thyroid gland was observed through entire observation period.