Seasonal changes in morphology of the thyroid gland of a hibernator, Spermophilus richardsoni

1981 ◽  
Vol 59 (6) ◽  
pp. 1022-1031 ◽  
Author(s):  
Brent W. Winston ◽  
Nancy E. Henderson
Keyword(s):  
Thyroid Gland ◽  
Seasonal Changes ◽  
Thyroid Tissue ◽  
Ground Squirrels ◽  
Physiological Data ◽  
Thyroid Cell ◽  
Apparent Contradiction ◽  
Dense Granules ◽  
Apical Vesicles ◽  
Circulating Levels

Seasonal changes in morphology of the thyroid gland were studied in Richardson's ground squirrels, Spermophilus richardsoni. Animals were sampled at six times during the annual cycle, and thyroid tissue was examined at the light and electron microscope levels. Synthesis and resorption of thyroglobulin were assessed on the bases of numbers of apical vesicles, colloid droplets, dense granules, and dense bodies, development of the Golgi apparatus and RER, and number and appearance of microvilli and mitochondria.Synthetic and resorptive activities of the throid-hormone-producing cells are high during the early prehibernation or preparative phase and decrease to moderate levels before entry into hibernation. Onset of hibernation is accompanied by further reductions in thyroid cell activities which reach minimal levels by midhibernation. Synthetic and resorptive functions increase slightly toward the end of hibernation. The reproductive phase following emergence is marked by a return to high levels of activities. Colloid storage in the follicles increases between early prehibernation and midhibernation and then decreases. The morphological observations suggest that triiodo-L-thyronine (T3) and L-thyroxine (T4) production and secretion are markedly reduced in hibernating ground squirrels. However, measurements of the circulating levels of the hormones have shown that the titres of both T3 and T4 are elevated in hibernating animals. The apparent contradiction between morphological and physiological data is discussed.

scholarly journals Immunocytochemical localization of cathepsins B, H, L, and T4 in follicular cells of rat thyroid gland.

1989 ◽  
Vol 37 (5) ◽  
pp. 691-696 ◽  
Author(s):  
Y Uchiyama ◽  
T Watanabe ◽  
M Watanabe ◽  
Y Ishii ◽  
H Matsuba ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Thyroid Tissue ◽  
Double Immunostaining ◽  
Follicular Cells ◽  
Thin Sections ◽  
Dense Granules ◽  
Dense Bodies ◽  
Rat Thyroid ◽  
Monospecific Antibodies ◽  
Rat Thyroid Gland

To localize cathepsins B, H, and L in follicular cells of rat thyroid gland, we applied immunocytochemistry to the thyroid tissue using their respective monospecific antibodies. On serial semi-thin sections, cathepsins B, H, and L were localized in granules of various sizes located throughout the cytoplasm, whereas T4 was detected in larger granules located in the apical and supranuclear regions. By electron microscopy, cathepsins B, H, and L were localized in large less-dense granules (so-called colloid droplets) and in dense bodies of various sizes, whereas T4 was localized more intensely in large less-dense granules than in smaller dense bodies. By double immunostaining using an immunogold method, cathepsins H and B or L were co-localized in the same cytoplasmic granules. Moreover, immunoblotting demonstrated that proteins similar to cathepsins B, H, and L in the liver are present in the thyroid gland. These results suggest that cathepsins B, H, and L participate not only in degradation of thyroglobulin but in maturation of thyroid hormones, although it remains unknown whether all of them participate in the maturation process.

Seasonal Changes in the Fine Structure of the Basal Granular Cells of the Bat Thyroid

1967 ◽  
Vol 2 (3) ◽  
pp. 401-410
Author(s):  
E. A. NUNEZ ◽  
R. P. GOULD ◽  
D. W. HAMILTON ◽  
J. S. HAYWARD ◽  
S. J. HOLT
Keyword(s):  
Fine Structure ◽  
Seasonal Changes ◽  
Follicular Epithelium ◽  
Thyroid Cell ◽  
Basal Region ◽  
Basal Cells ◽  
Uniform Size ◽  
Thyroid Cells ◽  
Cytoplasmic Matrix ◽  
Dense Granules

The fine structure of the thyroid gland of non-hibernating, hibernating, and intermittently aroused hibernating bats was examined. It was found that in addition to the ordinary follicular cell, another widespread thyroid cell type is present in all bats examined. This cell is situated in the basal region of the thyroid follicle and is characterized by a cytoplasm full of secretory-like granules. In the basal cells of bats captured in April and June the granules consist of an extremely dense core and are of a uniform size averaging from 0.1-0.5 µ in diameter. In bats caught in August the solid dense granules vary greatly in size and large granules of diameters from 2 to 5 µ are common. These large granules are often found concentrated in groups in the most basal region of the follicular epithelium. Hibernating bats are characterized by partly or totally degranulated basal thyroid cells. The cytoplasmic granules in the partly degranulated cell vary greatly in appearance, ranging from solid dense granules to empty vesicles. In totally degranulated basal cells, empty vesicles fill the cytoplasmic matrix. The granular endoplasmic reticulum of the basal thyroid cell also shows seasonal changes, while the Golgi complex remains a well-developed organelle throughout the year. These observations suggest that the thyroid basal granular cell is involved in secretory activities; its possible functional role is discussed.

Demonstration of significant epidermal growth factor activity in murine thyroid tissue

1986 ◽  
Vol 110 (1) ◽  
pp. 67-72 ◽  
Author(s):  
S. Dagogo-Jack ◽  
S. Atkinson ◽  
P. Kendall-Taylor
Keyword(s):  
Growth Factor ◽  
Thyroid Gland ◽  
Epidermal Growth Factor ◽  
Thyroid Tissue ◽  
Submaxillary Gland ◽  
Biologically Active ◽  
Thyroid Cell ◽  
Submaxillary Glands ◽  
Epidermal Growth ◽  
Mouse Thyroid

ABSTRACT Epidermal growth factor (EGF) was first isolated from the mouse submaxillary gland (SMG) which remains its only known site of synthesis. Earlier work suggests that EGF may be implicated in the regulation of thyroid cell growth and proliferation. Moreover, thyroid hormones increase the EGF content of mouse SMG and mimic the maturational effects associated with EGF. The aim of this study was therefore to determine whether the mouse thyroid gland is a site of EGF production. Thyroid and submaxillary glands were homogenized in Tris-HCl, the EGF content was measured by a homologous radioimmumonassay (RIA) and receptor-binding activity assessed in a radioreceptor assay. Epidermal growth factor was readily detectable in each thyroid extract. Dilution curves were parallel to the standard curve. Values obtained for right and left lobes of thyroid were in excellent agreement (r = 0·997, P<0·001). The intrathyroidal EGF concentration obtained by RIA was 26·1 ± 6·0 (s.e.m.) ng/mg protein (n = 40); values obtained by the receptor assay were slightly lower but correlated closely (r = 0·828, P < 0·01). Assay of homogenates prepared at the same time from the submaxillary glands of these mice showed that thyroidal EGF was not correlated with EGF content in the SMG. These findings indicate that EGF, both biologically active and immunoreactive, is readily detectable in the mouse thyroid and that the thyroid gland is a probable site of EGF synthesis. The methodology provides a model for further studies of the regulation of EGF production and its significance in relation to thyroid disease. J. Endocr. (1986) 110, 67–72

TUMOURS OF THE HYPOPHYSIS AND THE THYROID IN MICE

1955 ◽  
Vol 18 (4) ◽  
pp. 445 ◽  
Author(s):  
O. Mühlbock
Keyword(s):  
Thyroid Gland ◽  
Radioactive Iodine ◽  
Thyroid Tissue ◽  
Prolonged Treatment ◽  
Genetic Constitution ◽  
Thiouracil Derivatives

SUMMARY Hypophyseal tumours in mice develop after prolonged treatment with oestrogens, after injection of radioactive iodine in doses which destroy the thyroid tissue and after prolonged treatment with thiouracil-derivatives. The tumours of the hypophysis only occur in certain strains of mice and hence the genetic constitution is of importance. The origin of this difference between strains has hitherto remained completely obscure. The hypophyseal tumours in mice seen following administration of oestrogens and those observed after destruction of the thyroid gland are morphologically similar. They consist of cells staining blue to varying degrees, and they may thus be termed amphophile tumours. The possible mechanism of development of the hypophyseal tumours has been discussed.

EPIDEMIC THYROIDITIS

1964 ◽  
Vol 45 (3) ◽  
pp. 381-401 ◽  
Author(s):  
G. Hintze ◽  
P. Fortelius ◽  
J. Railo
Keyword(s):  
Thyroid Gland ◽  
Distribution Pattern ◽  
Needle Biopsy ◽  
Serum Proteins ◽  
Acute Infection ◽  
Thyroid Tissue ◽  
Subacute Thyroiditis ◽  
Present Observation ◽  
Upper Respiratory Tract ◽  
Endemic Goitre

ABSTRACT A type of subacute thyroiditis occurring epidemically in a factory in Helsinki was observed in 44 cases. In every case the thyroiditis followed an acute infection of the upper respiratory tract. The variation in incidence during one and a half years was in good agreement with that of the acute infection. Since Helsinki is in an endemic goitre region, the fact that the disease was of the migrating type was of great diagnostic importance. In all cases but one, the nodules have persisted. One case of asymptomatic thyroiditis was seen. In the majority of the patients the thyroid gland had been carefully palpated before the thyroiditis occurred, and in all cases the condition was followed up by the same investigator. Special attention was paid to changes in the iodine metabolism, the serum cholesterol, the electrophoretic distribution pattern of the serum proteins, and the circulating thyroid auto-antibodies. In many cases needle biopsy of the thyroid gland was performed. Thyroid function invariably returned to normal with time, although one patient remained in a hypothyroid state for about a year. In no cases were thyroid auto-antibodies found. For the beta-globulin fraction, the electrophoretic distribution pattern of the serum proteins gave values which were still not normalized in any case, and only in two cases was the alpha2-fraction normalized. The needle biopsy, when thyroid tissue was obtained, showed almost the same picture as in endemic goitre, but in some specimens nonspecific inflammatory changes were seen. Prednisolone relieved the symptoms, but did not affect the course of the disease. According to the present observation this type of epidemic thyroiditis would seem to represent a form of nonspecific subacute thyroiditis.

Infants Diagnosed with Athyreosis on Scintigraphy May Have a Gland Present on Ultrasound and Have Transient Congenital Hypothyroidism

2021 ◽  
pp. 1-8
Author(s):  
Niamh McGrath ◽  
Colin Patrick Hawkes ◽  
Stephanie Ryan ◽  
Philip Mayne ◽  
Nuala Murphy
Keyword(s):  
Thyroid Gland ◽  
Congenital Hypothyroidism ◽  
Thyroid Tissue ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Ultrasound ◽  
Free T4 ◽  
Median Serum ◽  
Thyroid Glands ◽  
Rule Out

Scintigraphy using technetium-99m (<sup>99m</sup>Tc) is the gold standard for imaging the thyroid gland in infants with congenital hypothyroidism (CHT) and is the most reliable method of diagnosing an ectopic thyroid gland. One of the limitations of scintigraphy is the possibility that no uptake is detected despite the presence of thyroid tissue, leading to the spurious diagnosis of athyreosis. Thyroid ultrasound is a useful adjunct to detect thyroid tissue in the absence of <sup>99m</sup>Tc uptake. <b><i>Aims:</i></b> We aimed to describe the incidence of sonographically detectable in situ thyroid glands in infants scintigraphically diagnosed with athyreosis using <sup>99m</sup>Tc and to describe the clinical characteristics and natural history in these infants. <b><i>Methods:</i></b> The newborn screening records of all infants diagnosed with CHT between 2007 and 2016 were reviewed. Those diagnosed with CHT and athyreosis confirmed on scintigraphy were invited to attend a thyroid ultrasound. <b><i>Results:</i></b> Of the 488 infants diagnosed with CHT during the study period, 18/73 (24.6%) infants with absent uptake on scintigraphy had thyroid tissue visualised on ultrasound (3 hypoplastic thyroid glands and 15 eutopic glands). The median serum thyroid-stimulating hormone (TSH) concentration at diagnosis was significantly lower than that in infants with confirmed athyreosis (no gland on ultrasound and no uptake on scintigraphy) (74 vs. 270 mU/L), and median free T4 concentration at diagnosis was higher (11.9 vs. 3.9 pmol/L). Six of 10 (60%) infants with no uptake on scintigraphy but a eutopic gland on ultrasound had transient CHT. <b><i>Conclusion:</i></b> Absent uptake on scintigraphy in infants with CHT does not rule out a eutopic gland, especially in infants with less elevated TSH concentrations. Clinically, adding thyroid ultrasound to the diagnostic evaluation of infants who have athyreosis on scintigraphy may avoid committing some infants with presumed athyreosis to lifelong levothyroxine treatment.

scholarly journals Developing anterior mediastinum mass after orthotopic thyroidectomy: a case report

2020 ◽  
Vol 51 (1) ◽  
Author(s):  
Rita Meira Soares Camelo ◽  
José Maria Barros
Keyword(s):  
Thyroid Gland ◽  
Total Thyroidectomy ◽  
Thyroid Tissue ◽  
Anterior Mediastinum ◽  
Ectopic Thyroid ◽  
Ectopic Thyroid Tissue ◽  
Ectopic Tissue ◽  
Thyroid Scan ◽  
Imaging Results ◽  
Adjacent Structures

Abstract Background Ectopic thyroid tissue is a rare embryological aberration described by the occurrence of thyroid tissue at a site other than in its normal pretracheal location. Depending on the time of the disruption during embryogenesis, ectopic thyroid may occur at several positions from the base of the tongue to the thyroglossal duct. Ectopic mediastinal thyroid tissue is normally asymptomatic, but particularly after orthotopic thyroidectomy, it might turn out to be symptomatic. Symptoms are normally due to compression of adjacent structures. Case presentation We present a case of a 66-year-old male submitted to a total thyroidectomy 3 years ago, due to multinodular goiter (pathological results revealed nodular hyperplasia and no evidence of malignancy), under thyroid replacement therapy. Over the last year, he developed hoarseness, choking sensation in the chest, and shortness of breath. Thyroid markers were unremarkable. He was submitted to neck and thoracic computed tomography, magnetic resonance imaging, and radionuclide thyroid scan. Imaging results identified an anterior mediastinum solid lesion. A radionuclide thyroid scan confirmed the diagnosis of ectopic thyroid tissue. The patient refused surgery. Conclusions Ectopic thyroid tissue can occur either as the only detectable thyroid gland tissue or in addition to a normotopic thyroid gland. After a total thyroidectomy, thyroid-stimulating hormone can promote a compensatory volume growth of previously asymptomatic ectopic tissue. This can be particularly diagnosis challenging since ectopic tissue can arise as an ambiguous space-occupying lesion.

scholarly journals Submandibular ectopic thyroid gland: an uncommon presentation

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Inès Riahi ◽  
Rim Fradi ◽  
Ibtissem Ben Nacef ◽  
Ahlem Blel
Keyword(s):  
Thyroid Gland ◽  
Thyroid Tissue ◽  
Ectopic Thyroid ◽  
Lingual Thyroid ◽  
Submandibular Region ◽  
Case Presentation ◽  
Thyroglossal Duct ◽  
Common Presentation ◽  
Ectopic Thyroid Tissue ◽  
Uncommon Presentation

Abstract Background Ectopic thyroid is a developmental anomaly of the thyroid gland of embryological origin. Instead of having a pretracheal situation, thyroid tissue is elsewhere, most commonly in the median cervical line along the course of the thyroglossal duct. Lingual thyroid is the most common presentation. Ectopic thyroid tissue in the submandibular region has been rarely reported. Case presentation We report herein a case of a 65-year-old man admitted to our department with a complaint of a painless swelling in the left submandibular region. Conclusions Thyroid gland ectopia should be considered among the differential diagnoses of submandibular swelling. Ectopic thyroid tissue can present with the same pathology affecting the normal thyroid gland such as malignancy and hyperthyroidism.

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