IODINATED THYROLIPIDS: THEIR POSSIBLE ROLE IN HORMONOGENESIS

1973 ◽  
Vol 74 (3) ◽  
pp. 461-474 ◽  
Author(s):  
D. H. Shah ◽  
U. R. Thakare ◽  
R. C. Shownkeen ◽  
D. N. Pahuja ◽  
M. Y. Mandlik
Keyword(s):  
Thyroid Gland ◽  
Lipid Fraction ◽  
Human Thyroid ◽  
Cystic Degeneration ◽  
Nodular Goitre ◽  
Thyroid Glands ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

ABSTRACT A total of 42 human thyroid glands (nodular goitre 9, adenoma with cystic degeneration 6; toxic goitre 10; carcinoma 14; and normal thyroid gland 3) were examined in vitro for iodination of an unidentified polar non-phosphatide lipid fraction (fraction II). The radioiodine incorporation in fraction II was 49.3 %, 43.6 %, 32.8 %, 20.7 %, and 22.0 % respectively in normal, nodular goitre, adenoma with cystic degeneration, toxic goitre and thyroid carcinoma. In vitro studies with surviving sheep thyroid slices did not show any relation between the iodination of fraction II and thyroxine formation over a period of 120 min. However, a highly significant correlation (r-value= 0.96375) was observed between the iodination of fraction II and thyroxine formation in vivo in the rat thyroid gland over a period of 24 h. We have previously postulated that iodination of fraction II may be interrelated to thyroxine formation. In the light of this hypothesis and the above results we suggest that the iodination of fraction II and thyroxine formation in the thyroid gland may be interrelated, the degree of iodination of fraction II being modulated by the amount of thyroxine formed within the thyroid gland.

scholarly journals Acrylamide does not induce tumorigenesis or major defects in mice in vivo

2008 ◽  
Vol 198 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Ling Jin ◽  
Vanessa Chico-Galdo ◽  
Claude Massart ◽  
Christine Gervy ◽  
Viviane De Maertelaere ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Chronic Administration ◽  
Serum Levels ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Hormone Synthesis ◽  
Rat Thyroid

Chronic administration of acrylamide has been shown to induce thyroid tumors in rat. In vitro acrylamide also causes DNA damage, as demonstrated by the comet assay, in various types of cells including human thyroid cells and lymphocytes, as well as rat thyroid cell lines. In this work, mice were administered acrylamide in their drinking water in doses comparable with those used in rats, i.e., around 3–4 mg/kg per day for mice treated 2, 6, and 8 months. Some of the mice were also treated with thyroxine (T4) to depress the activity of the thyroid. Others were treated with methimazole that inhibits thyroid hormone synthesis and consequently secretion and thus induces TSH secretion and thyroid activation. These moderate treatments were shown to have their known effect on the thyroid (e.g. thyroid hormone and thyrotropin serum levels, thyroid gland morphology…). Besides, T4 induced an important polydipsia and degenerative hypertrophy of adrenal medulla. Acrylamide exerted various discrete effects and at high doses caused peripheral neuropathy, as demonstrated by hind-leg paralysis. However, it did not induce thyroid tumorigenesis. These results show that the thyroid tumorigenic effects of acrylamide are not observed in another rodent species, the mouse, and suggest the necessity of an epidemiological study in human to conclude on a public health policy.

scholarly journals Ultrastructure of blebbing and phagocytosis of blebs by hyperplastic thyroid epithelial cells in vivo.

1977 ◽  
Vol 72 (3) ◽  
pp. 584-594 ◽  
Author(s):  
J D Zeligs ◽  
S H Wollman
Keyword(s):  
Thyroid Gland ◽  
Epithelial Cells ◽  
Cultured Cells ◽  
Ultrastructural Organization ◽  
Contractile Ring ◽  
Phagocytic Process ◽  
Different Types ◽  
Rat Thyroid

In addition to pseudopods, somewhat pleomorphic blebs were consistently found protruding from the apical surfaces of hyperplastic rat thyroid epithelial cells into the follicular lumens in vivo. Many blebs were knobby, roughly hemispherical protrusions, with a diameter of 2-3 mum. Such blebs had a densely packed microfilamentous core and contained numerous apparent ribosomes. They were morphologically similar to blebs that have been observed in a variety of cultured cells. Other blebs were larger, more elongate, and less knobby, but had a similar ultrastructural organization. Blebs of all sizes appeared to be phagocytosed on some occasions by nearby epithelial cells. The phagocytic process involved partial engulfment of the bleb by a typical epithelial pseudopod, followed by an apparent pinching-off process, presumably resulting in the separation of the bleb from its cells or origin. The pinching-off process was associated with a band of approx. 6-nm diameter microfilaments that developed within the pseudopod cytoplasm surrounding the base of the bleb and is postulated to function as a contractile ring. The finding of blebbing is an intact tissue in vivo indicates that this phenomenon is not restricted to cultured cells, and thus tends to extend the significance of in vitro observations of the process. In relation to their occurrence in the hyperplastic thyroid gland in vivo, possible interconversions are considered between different types of blebs, and between blebs and pseudopods.

INABILITY OF HETEROLOGOUS ANTIBODIES TO AFFECT RAT THYROID GLAND

1961 ◽  
Vol 39 (4) ◽  
pp. 691-694 ◽  
Author(s):  
H. S. Sodhi
Keyword(s):  
Thyroid Gland ◽  
Thyroid Antibodies ◽  
Specific Antibodies ◽  
Thyroid Glands ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

Heterologous rat thyroid antibodies produced in rabbits were injected by intraperitoneal, intravenous, and intra-arterial routes in different groups of rats and the effects on the morphology and 24-hour I131 uptake of their thyroid glands were investigated. In spite of the administration of high titers of specific antibodies no effects, acute or chronic, were observed, indicating the inability of the heterologous thyroid antibodies to alter the structure or function of the rat thyroid glands.

Control of thyroglobulin secretion from the rat thyroid gland

1984 ◽  
Vol 101 (1) ◽  
pp. 107-111 ◽  
Author(s):  
E. G. Black ◽  
M. C. Sheppard ◽  
R. Hoffenberg
Keyword(s):  
Thyroid Stimulating Hormone ◽  
Dependent Manner ◽  
Serum Thyroglobulin ◽  
Thyroid Cells ◽  
Normal Rat ◽  
Rat Thyroid ◽  
Dose Dependent ◽  
Rat Thyroid Gland

ABSTRACT Serum thyroglobulin (Tg), measured by radioimmunoassay, was high in 6-propylthiouracil (PTU)-treated rats but low in thyroxine (T4)-treated animals compared with euthyroid controls. Thyroid-stimulating hormone (TSH) stimulated Tg release in vitro from enzymatically dispersed normal rat thyroid cells in a dose-dependent manner. Thyroid cells prepared from T4-treated animals behaved similarly to cells from control rats, whereas in vitro basal release of Tg from thyroid cells prepared from PTU-treated animals was high and the response to TSH was lost. Our data confirm the TSH dependency of Tg release in vivo and in vitro and our system provides a means of studying the control of Tg secretion in vitro. J. Endocr. (1984) 101, 107–111

scholarly journals Radioautographic studies of the initial site of formation of protein-bound iodine in the rat thyroid gland

1970 ◽  
Vol 118 (2) ◽  
pp. 311-314 ◽  
Author(s):  
C. J. Croft ◽  
Rosalind Pitt-Rivers
Keyword(s):  
Thyroid Gland ◽  
Peripheral Portion ◽  
Thyroid Glands ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

1. Predominantly cellular labelling was observed in radioautographs of rat thyroid glands fixed by perfusion from the aorta at intervals between 5 and 55s after [125I]iodide administration via the aorta. 2. When perfusion was delayed for 2min, or if immersion fixation was used, the labelling was predominantly over the peripheral portion of the follicular lumen, in agreement with the observations of other investigators. 3. The findings support the concept that the initial site of binding of iodine to protein is intracellular, but the nature of this protein has not been established.

IODINATED PARTICLES IN THE RAT THYROID

1975 ◽  
Vol 79 (3) ◽  
pp. 459-473 ◽  
Author(s):  
J. Dang ◽  
R. Miquelis ◽  
P. Bastiani ◽  
C. Simon
Keyword(s):  
Acid Phosphatase ◽  
Thyroid Gland ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
High Turnover ◽  
Secondary Lysosomes ◽  
Rat Thyroid ◽  
Tsh Stimulation

ABSTRACT In a previous study (Simon et al. 1971) a procedure for the preparation and separation of iodinated particles was described in the rat. The present paper deals with further investigations on the nature of these particles. Acid phosphatase and iodine are conjointly sedimentable and display a latency that is unmasked on dilution in a hypo-osmotic medium and under acidification to pH 5.0. These properties together with the sensitivity to Triton X-100 are best accounted for by assuming that iodinated particles of the thyroid gland are lysosomes. Part of the particulate iodine is soluble in n-butanol (BEI fraction). The existence of this BEI fraction demonstrates that hydrolysis of thyroglobulin occurs within the particles which thus exhibit an acid protease activity. Both the sedimentable iodine pool and acid phosphatase are increased under TSH stimulation and decreased after thyroxine treatment. In addition, the general activity of the iodinated particles is dependent on the daily iodine intake as shown by the variation of their iodine pool, acid phosphatase activity and BEI fraction with the iodine diet. It is concluded that iodinated particles of the thyroid gland are secondary lysosomes which participate in iodine secretion under TSH control. By in vitro treatment with destabilizing media or after in vivo treatment with thyroxine, iodinated particles exhibit a parallel loss of iodine and acid phosphatase. After a short-term TSH treatment in vivo, their iodine pool is more increased than their acid phosphatase activity. It is concluded that, at least in the normal rat thyroid, iodinated particles are essentially secondary lysosomes; true colloid droplets actually accumulate only after sufficient TSH stimulation. After ultracentrifugation, 3 main subpopulations are separated for which iodine and acid phosphatase patterns are superimposed. In addition, they all exhibit properties characteristic of secondary lysosomes. Finally, the presence of a fourth sedimentable iodinated fraction with a high turnover rate is postulated.

N,N’ -Bis (4-Aminophenyl) -N,N'-Dimethylethylenediamine (BED) Oxidation In Rat Thyroid Gland

1976 ◽  
Vol 34 ◽  
pp. 90-91
Author(s):  
W. Allen Shannon
Keyword(s):  
Thyroid Gland ◽  
Parotid Gland ◽  
Nuclear Envelope ◽  
Rat Liver ◽  
Cytoplasmic Membrane ◽  
Membrane Activity ◽  
Outer Compartment ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

Ultracytochemical oxidation studies with N,N'-bis(4-aminophenyl)-N,N'-dimethylethylenediamine (BED) have been previously reported. Reaction variations related to fixation have been studied in rat liver and parotid gland. It is thought that in vitro oxidation of the compound demonstrates two different oxidative systems. They are represented by 1) mitochondrial outer compartment activity and 2) cytoplasmic membrane activity, i.e. Golgi, ER and nuclear envelope. Unlike the latter activity, the former one exhibits considerable sensitivity toward formaldehyde fixation. Further investigation with this compound in rat thyroid gland has revealed oxidative activity in mitochondrial cristae in addition to that present in the outer compartment and membranes of other organelles.

Sign in / Sign up

Export Citation Format

Share Document