Site of Iodination in Hyperplastic Thyroid Glands Deduced from Autoradiographs*

Wollman, Seymour H.; Ekholm, R.

doi:10.1210/endo-108-6-2082

Cited by 16 publications

(2 citation statements)

References 3 publications

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“…Uptake of iodide into the thyroid follicle cell is facilitated by the sodium‐iodide symporter at the basolateral membrane [37], and apical efflux into the follicular lumen probably is facilitated by pendrin, a transport protein in the apical surface of the cell [38]. In the rat thyroid follicle, radioactive iodide seems to accumulate at the apical surface of the epithelium shortly after administration of the radiotracer, thus forming a ring around the periphery of the colloid [39,40]. The location and appearance of this iodide ring is similar to the colloidal T 4 ring observed in zebrafish [32; present], medaka, and rainbow trout [31] thyroid follicles.…”

Section: Discussionmentioning

confidence: 99%

Novel biomarkers of perchlorate exposure in zebrafish

Mukhi

Carr

Anderson

et al. 2005

Enviro Toxic and Chemistry

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Perchlorate inhibits iodide uptake by thyroid follicles and lowers thyroid hormone production. Although several effects of perchlorate on the thyroid system have been reported, the utility of these pathologies as markers of environmental perchlorate exposures has not been adequately assessed. The present study examined time-course and concentration-dependent effects of perchlorate on thyroid follicle hypertrophy, colloid depletion, and angiogenesis; alterations in whole-body thyroxine (T4) levels; and somatic growth and condition factor of subadult and adult zebrafish. Changes in the intensity of the colloidal T4 ring previously observed in zebrafish also were examined immunohistochemically. Three-month-old zebrafish were exposed to ammonium perchlorate at measured perchlorate concentrations of 0, 11, 90, 1,131, and 11,480 ppb for 12 weeks and allowed to recover in clean water for 12 weeks. At two weeks of exposure, the lowest-observed-effective concentrations (LOECs) of perchlorate that induced angiogenesis and depressed the intensity of colloidal T4 ring were 90 and 1,131 ppb, respectively; other parameters were not affected (whole-body T4 was not determined at this time). At 12 weeks of exposure, LOECs for colloid depletion, hypertrophy, angiogenesis, and colloidal T4 ring were 11,480, 1,131, 90, and 11 ppb, respectively. All changes were reversible, but residual effects on angiogenesis and colloidal T4 ring intensity were still present after 12 weeks of recovery (LOEC, 11,480 ppb). Whole-body T4 concentration, body growth (length and weight), and condition factor were not affected by perchlorate. The sensitivity and longevity of changes in colloidal T4 ring intensity and angiogenesis suggest their usefulness as novel markers of perchlorate exposure. The 12-week LOEC for colloidal T4 ring is the lowest reported for any perchlorate biomarker in aquatic vertebrates.

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Section: Discussionmentioning

confidence: 99%

Novel biomarkers of perchlorate exposure in zebrafish

Mukhi

Carr

Anderson

et al. 2005

Enviro Toxic and Chemistry

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“…In thyrocytes it has been shown that not only mature but also part of the immature APP is iodinated. As iodination is restricted to the plasma membrane (Wollman and Ekholm 1981) this finding indicates that a fraction of the immature APP may reach the plasma membrane (Graebert et al 1995a). From the plasma membrane APP is either endocytosed and degraded with a half-life of about 30 min (Weidemann et al 1989;Graebert et al 1995a) or released into the extracellular space (Fig.…”

Section: Topology Of Proteolytic Aβ and Sapp Releasementioning

confidence: 99%

The biological role of the Alzheimer amyloid precursor protein in epithelial cells

Schmitz

Tikkanen

Kirfel

et al. 2001

Histochem Cell Biol

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Proteolytic processing of the Alzheimer amyloid precursor protein (APP) results in the generation of at least two distinct classes of biologically relevant peptides: (1) the amyloid beta peptides which are believed to be involved in the pathogenesis of Alzheimer's disease and (2) the soluble N-terminal ectodomain (sAPP) which exhibits a protective but as yet ill-defined effect on neurons and epithelial cells. In this report we present an overview on the functions of sAPP as an epithelial growth factor. This function involves specific binding of sAPP to membrane rafts and results in signal transduction and various physiological effects in epithelial cells as different as keratinocytes and thyrocytes. At nanomolar concentrations sAPP induces a two to fourfold increase in the rate of cell proliferation and cell migration. Specific inhibition of APP expression by antisense techniques results in decreased sAPP release and in reduced proliferative and motogenic activities. Proliferation and migration are known to be part of complex processes such as wound healing which, therefore, might be facilitated by the growth factor function of sAPP.

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Monoiodotyrosine formation during thyroglobulin processing in golgi vesicles

Bastiani

Rognoni

1988

Cell Biochemistry & Function

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A golgi-enriched subfraction was obtained from porcine thyroid glands by differential centrifugation. When incubated in a suitable medium, these vesicles were able to concentrate iodide from the medium and bind it to protein. The iodination process was inhibited by methylmercapto-imidazole and was increased by the addition of an H2O2 generating system to the medium. Analysis of the protein content of the vesicles revealed the presence of 18 and 12-13 S thyroglobulin molecules, lacking mannose residues, and containing only monoiodotyrosine. It is concluded that in vitro, iodination can begin before exocytosis, in the smooth-surfaced vesicles derived from the golgi apparatus, as soon as N-acetylglucosamine is incorporated onto the pre-thyroglobulin molecule.

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Site of Iodination in Hyperplastic Thyroid Glands Deduced from Autoradiographs*

Cited by 16 publications

References 3 publications

Novel biomarkers of perchlorate exposure in zebrafish

Novel biomarkers of perchlorate exposure in zebrafish

The biological role of the Alzheimer amyloid precursor protein in epithelial cells

Monoiodotyrosine formation during thyroglobulin processing in golgi vesicles

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