IODINATED PARTICLES IN THE RAT THYROID I. A RAPID SEPARATION METHOD

ABSTRACT In a first step, the quantitative preparation of the whole population of iodinated particles was reinvestigated in thyroids obtained from rats maintained in an isotopic equilibrium with 125I. The maximum yield in the iodinated particles was obtained for a 0.15 m sucrose solution in 0.1 m Tris-HCl buffer pH 7. This yield was 3.5 % and 1.7 % of the total iodine content of the thyroid for rats adapted to receive 50 (group 50) and 5 μg (group 5) of iodine daily respectively. The iodinated particles of group 50 were found to be more sensitive to pH variations than those of group 5. In a second step, a rapid method was developed to separate the whole population of iodinated particles into physiological populations (tentatively colloid droplets and secondary lysosomes). By centrifuging onto a discontinuous Ficoll gradient, three distinct iodine peaks were regularly obtained for rats of group 5 and 50 and also for other rats receiving a diet rich in iodine. For group 50, the iodine pools (127I) as measured by isotopic equilibrium were found to represent about 16% (peak 1), 25 % (peak 2) and 59 % (peak 3) of the total particulate iodine content of the gland. The possible nature of these three populations of iodinated particles is discussed.

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Calcium and metabolism of I131 in rats and homogenates of rat thyroid

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1961.200.5.1023 ◽

1961 ◽

Vol 200 (5) ◽

pp. 1023-1026 ◽

Cited By ~ 5

Author(s):

Yaro Ribeiro Gandra ◽

John G. Coniglio

Keyword(s):

Thyroid Tissue ◽

Iodine Content ◽

In Vitro Studies ◽

Iodine Uptake ◽

Total Iodine ◽

Organic Iodine ◽

Free Iodine ◽

Inorganic Iodine ◽

Rat Thyroid

The goitrogenic effect of calcium was studied by the use of I131 in intact rats and in rat thyroid slices. Rats receiving excess dietary calcium had larger thyroids than controls. Enlargement of the thyroid was accompanied by increased content of inorganic iodine and decreased content of organic iodine. In vitro studies showed that thyroid enlargement was associated with greater total iodine uptake. Addition of calcium to the incubation medium decreased the total iodine uptake of thyroid slices. The reduction occurred as a consequence of interference with the conversion of inorganic iodine to organic iodine. No decrease in inorganic iodine content was observed. The ratios of bound iodine to free iodine were constantly smaller in the thyroid groups receiving calcium supplement. The results of the in vitro studies suggest that calcium interference is due, at least in part, to a direct effect on thyroid tissue.

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LONG-TERM TURNOVER OF THYROID IODINE IN THE RAT AS STUDIED BY THE ISOTOPIC EQUILIBRIUM METHOD

Acta Endocrinologica ◽

10.1530/acta.0.0850357 ◽

1977 ◽

Vol 85 (2) ◽

pp. 357-363 ◽

Cited By ~ 5

Author(s):

Paul Bastiani ◽

Claude Simon

Keyword(s):

Steady State ◽

Iodine Intake ◽

Isotopic Equilibrium ◽

Total Iodine ◽

Equilibrium Method ◽

Plasma Hormones ◽

Group 5 ◽

Slow Turnover ◽

Made In

ABSTRACT A long-term kinetics study was made in rats in a steady state for iodine metabolism and receiving either 5 μg iodine (group 5) or 50 μg iodine (group 50) daily. By using the isotopic equilibrium method, the value of the renewed fraction was followed during at least 120 days in the thyroglobulin (Tg) and the lysosomes of the thyroid and in the plasma hormones. For both groups, only part of the total iodine pool in the Tg as well as in the lysosomes is directly available for secretion. Furthermore, the direct precursor pool of iodine for secretion in the lysosomes is dependent on the daily iodine intake (1.3 times greater in group 50 than in group 5) while the Tg iodine supply in the colloid is not (80 % of the total Tg iodine pool for both groups). An iodine pool with a very slow turnover is present in the lysosomes (about 50 % in each group), in the Tg of group 5 (more than 15 %) and probably in the Tg of group 50 (less than 5 %). Thus, the distribution of such a pool between lysosomes and Tg is dependent on the daily iodine intake. The very slow iodine pool is probably not accumulated into the follicles, since every studied pool is in steady state. It is practically not secreted since hormones in the plasma are entirely renewed. Again, it is practically not deiodinated since the thyroid iodide pool is also entirely renewed. These three criteria are valuable for both groups. Although one cannot entirely exclude its participation in secretion, it is postulated that the major part of this pool is re-cycled without deiodination. Both lysosome-lysosome and lysosome-colloid pathways of re-cycling have been postulated. The second pathway is supposed to increase when the daily iodine intake is decreased.

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DIE ZUSAMMENSETZUNG DER JODHALTIGEN VERBINDUNGEN UND IHRE BEZIEHUNG ZUM JODUMSATZ IN EUTHYREOTEN STRUMEN

Acta Endocrinologica ◽

10.1530/acta.0.0410584 ◽

1962 ◽

Vol 41 (4) ◽

pp. 584-594 ◽

Cited By ~ 2

Author(s):

Dankwart Reinwein ◽

Erich Klein

Keyword(s):

Column Chromatography ◽

Iodine Content ◽

High Plasma ◽

Secretion Rate ◽

Total Iodine ◽

Iodine Compound ◽

Hormonal Secretion ◽

Carrier Free ◽

Iodine Metabolism ◽

Diffuse Goiter

ABSTRACT The iodine metabolism was investigated in 29 patients with euthyroid non-endemic diffuse goiter. 1 to 14 days before thyroidectomy the patients received carrier-free 131I. The chemical iodine fractions (PBI, BEI and iodide) of the thyroid and the labelled iodine compound were analyzed by means of paper- and column chromatography. In one gland the total iodine content varied only by ± 19.6% of the average, the relative shares of PBI, BEI and iodide as well as that of the iodoamino acids being equal. Monoiodotyrosine, diiodotyrosine and thyroxine were found in the thyroid homogenate without hydrolysis. The homogenate after hydrolysis contained more iodotyrosines at the expense of iodothyronines than do normal glands. 17 goiters with normal 131I-uptake showed a high total iodine content (14.2 ± 5.0 mg) whilst 9 goiters with an increased 131I-uptake had low values (3.58 ± 0.6 mg). The opposite was found for the relative shares of BEI with the chromatographically isolated iodothyronines thyroxine, triiodothyronine and an unidentified iodine compound. Goiters with »high plasma PB131I« were characterized by a faster transfer of 131I into the more heavily iodinated compounds than is found in glands with a normal hormonal secretion rate. The highest values for the iodothyronines were found in goiters with increased 131I-uptake together with a high hormonal secretion rate. From this study it appears that the changes in the iodine-poor glands are due to a defective exo- or endogenous iodine supply. The observed alterations in iodine-rich glands are probably induced by a faulty iodine utilization characterized by an incomplete iodotyrosyl-coupling defect.

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INFLUENCE OF ANTERIOR PITUITARY SUBSTANCES ON THE TOTAL IODINE CONTENT OF THE THYROID GLAND IN THE YOUNG DUCK

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)76359-x ◽

1932 ◽

Vol 95 (1) ◽

pp. 89-94

Author(s):

J.A. Schockaert ◽

G.L. Foster

Keyword(s):

Thyroid Gland ◽

Anterior Pituitary ◽

Iodine Content ◽

Total Iodine

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Iodine and iodothyronine content in human neonate thyroid gland

Archives of Biological Sciences ◽

10.2298/abs0204069s ◽

2002 ◽

Vol 54 (3-4) ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

Svetlana Savin-Zegarac ◽

Dubravka Cvejic ◽

Olgica Nedic ◽

R. Radosavljevic ◽

Ivana Petrovic

Keyword(s):

Thyroid Gland ◽

Gestational Age ◽

Thyroid Tissue ◽

Iodine Content ◽

Postnatal Life ◽

Total Iodine ◽

Mean Values ◽

Human Neonate ◽

The Mean ◽

Human Neonates

A few years after the iodine content of salt in Serbia was increased from 7 to 15 mg/kg NaCI, iodine, thyroxine (T4) and triiodothyronine (T3) concentrations were measured in thyroid tissue obtained at autopsy from 21 human neonates who died within 30 days after birth. The thyroidal iodine as well as T4 and T3 content per gland in?creased progressively with gestational age of human neonates (r = 0.73, 0.70 and 0.67 respectively, p < 0.001). In seven newborns (gestational age 36 to 41 weeks) the mean values for total iodine, T4 and T3 per gland were 109.1 ?g, 52.2 ?g and 4.4 ?g respectively. The results of iodine and iodothyroninc content found in neonatal thyroid gland, particularly at the end of gestation and a few days of postnatal life, indicates that the iodine supply was satisfactory.

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The total Iodine and Iodate-iodine content of sea-water

Deep Sea Research (1953) ◽

10.1016/0146-6313(60)90004-6 ◽

1960 ◽

Vol 7 (1) ◽

pp. 24-34 ◽

Cited By ~ 28

Author(s):

Richard A. Barkley ◽

Thomas G. Thompson

Keyword(s):

Sea Water ◽

Iodine Content ◽

Total Iodine

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Iodine content in consumer hen eggs

Veterinární Medicína ◽

10.17221/5526-vetmed ◽

2012 ◽

Vol 51 (No. 3) ◽

pp. 93-100 ◽

Cited By ~ 17

Author(s):

J. Travnicek ◽

V. Kroupova ◽

I. Herzig ◽

J. Kursa

Keyword(s):

Czech Republic ◽

Correlation Coefficient ◽

Daily Intake ◽

Iodine Content ◽

Egg Yolk ◽

Human Nutrition ◽

Total Iodine ◽

Fresh Matter ◽

The Czech Republic

This paper presents the latest information about the supply of iodine to meet its requirements in hens of laying type, on the basis of iodine content in egg yolk and about the importance of eggs as an iodine source in human nutrition. The Sandell-Kolthoff method was applied to determine iodine content in the yolk of eggs from 9 large flocks (54 eggs) and 16 small flocks (96 eggs) in 2004, and from 10 large flocks (135 eggs) and 15 small flocks (114 eggs) in 2005. Iodine content was also determined in the albumen of 70 eggs. In 2004, the iodine content in the yolk of eggs from large flocks was 1 014.1 ± 356.6 while in 2005 it amounted to 1 663.8 ± 1 179.7 µg/kg fresh matter (P < 0.01); the respective values for the yolk of eggs from small flocks in 2004 and 2005 were 307.1 ± 255.7 and 519.5 ± 508.2 µg/kg fresh matter (P < 0.01). Compared to 1996, in 2005, the iodine content in yolk increased by 123.7% in large flocks, and by 19.2% in small flocks. The iodine content in albumen was 16.2 ± 9.7 µg/kg fresh matter, and it accounted for 2.6–5.0% of the total iodine content in 1 egg. The correlation coefficient between iodine contents in yolk and albumen was r = 0.67. In the Czech Republic, 1 egg from large flocks contains on average 31.2 µg iodine while 1 egg from small flocks contains 10.0 µg. Eggs from large flocks cover 7–14% and from small flocks 2.2–4.4% of the daily iodine requirement in adults. Iodine concentrations exceeding 2 500 µg/kg yolk fresh matter in large flocks were measured between week 32 and 60 of the laying cycle and with daily intake of 0.116–0.132 mg iodine per hen.

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