scholarly journals Estimation of the C-cell numbers in rat thyroid glands using the optical fractionator.

1996 ◽  
Vol 44 (9) ◽  
pp. 997-1003 ◽  
Author(s):  
R E Feinstein ◽  
E Westergren ◽  
E Bucht ◽  
H E Sjöberg ◽  
L Grimelius
Keyword(s):  
Serum Levels ◽  
C Cells ◽  
Stereological Method ◽  
Cell Numbers ◽  
C Cell ◽  
Glass Slides ◽  
Thyroid Glands ◽  
Optical Fractionator ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

We estimated the total number of calcitonin-immunoreactive C-cells in rat thyroid gland using the optical fractionator, the unbiased stereological method for estimation of numbers. It was necessary first to use a fixative composed of formalin, acetic acid, and ethanol to distinctly visualize the C-cells. The 40-microm-thick sections had to adhere to chromalum-gelatin-coated Superfrost Plus glass slides, and the immunostaining technique had to stain the C-cells evenly throughout the whole sections. Because the C-cells were irregularly distributed in the thyroid tissues, their counting required screening of about 500 fields per lobe, but the number of C-cells counted need not be high, about 90 per lobe. We estimated that rats have 185,000 +/- 42,000 C-cells (mean +/- SD; n - 7). The C-cell population did not differ significantly between the two lobes of a given rat, but it varied markedly among rats. The biological differences among the animals contributed 83% to the observed variability, whereas the methodological uncertainty contributed 17%. The serum levels of calcitonin and calcium were not closely correlated to the C-cell numbers. Our results indicate that variability in C-cell experiments can be reduced most effectively by increasing the number of animals used. However, the similar C-cell frequency found in the two thyroid lobes of each rat allows the use of one uniformly sampled lobe for quantification and the other lobe for further analysis.

Quantitative changes in the frequency and distribution of the C-cell population in the rat thyroid gland with age

1992 ◽  
Vol 270 (1) ◽  
pp. 73-77 ◽  
Author(s):  
I. Mart�n-Lacave ◽  
E. Conde ◽  
C. Montero ◽  
H. Galera-Davidson
Keyword(s):  
Thyroid Gland ◽  
Cell Population ◽  
C Cell ◽  
Quantitative Changes ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

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.

Postnatal variations in the number and size of C-cells in the rat thyroid gland

1995 ◽  
Vol 280 (3) ◽  
pp. 659-663 ◽  
Author(s):  
E. Conde ◽  
I. Mart�n-Lacave ◽  
J. C. Utrilla ◽  
R. Gonz�lez-C�mpora ◽  
H. Galera-Davidson
Keyword(s):  
Thyroid Gland ◽  
C Cells ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

Comparative immunohistochemical study of normal, hyperplastic and neoplastic C cells of the rat thyroid gland

2002 ◽  
Vol 309 (3) ◽  
pp. 361-368 ◽  
Author(s):  
Martín-Lacave I. ◽  
Rojas F. ◽  
Bernabé R. ◽  
Utrilla J. ◽  
Fernández-Santos J. ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Immunohistochemical Study ◽  
C Cells ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

Multiple calcium currents in a thyroid C-cell line: biophysical properties and pharmacology

1991 ◽  
Vol 260 (6) ◽  
pp. C1253-C1263 ◽  
Author(s):  
B. A. Biagi ◽  
J. J. Enyeart
Keyword(s):  
Cell Line ◽  
Time Constant ◽  
Calcium Currents ◽  
C Cells ◽  
Patch Clamp Technique ◽  
C Cell ◽  
Dependent Inactivation ◽  
Voltage Dependent ◽  
Rat Thyroid ◽  
Ca2 Channels

The whole cell version of the patch-clamp technique was used to characterize voltage-gated Ca2+ channels in the calcitonin-secreting rat thyroid C-cell line 6-23 (clone 6). Three types of Ca2+ channels could be distinguished based on differences in voltage dependence, kinetics, and pharmacological sensitivity. T-type current was half-maximal at -31 mV, showed steady-state voltage-dependent inactivation that was half-maximal at -57 mV, inactivated with a voltage-dependent time constant that reached a minimum of 20 ms at potentials positive to -20 mV, and deactivated with a single time constant of approximately 2 ms at -80 mV. Reactivation of inactivated channels occurred with a time constant of 1.26 s at -90 mV. T current was selectively blocked by Ni2+ at concentrations between 5 and 50 microM. La3+ and Y3+ blocked the T current at 10- to 20-fold lower concentrations. Dihydropyridine-sensitive L-type current was half-maximal at a test potential of -3 mV and was approximately doubled in size when Ba2+ replaced Ca2+ as the charge carrier. Unlike L-type Ca2+ current in many cells, this current in C-cells displayed little Ca(2+)-dependent inactivation. N-type current was composed of inactivating and sustained components that were inhibited by omega-conotoxin. The inactivating component was half-maximal at +9 mV and could be fitted by two exponentials with time constants of 22 and 142 ms. A slow inactivation of N current with a time constant of 24.9 s was observed upon switching the holding potential from -80 to -40 mV. These results demonstrate that, similar to other neural crest derived cells, thyroid C-cells express multiple Ca2+ channels, including one previously observed only in neurons.

CALCITONIN PRODUCTION BY RAT THYROID TUMOURS

1975 ◽  
Vol 66 (1) ◽  
pp. 37-43 ◽  
Author(s):  
S. M. TRIGGS ◽  
R. D. HESCH ◽  
J. S. WOODHEAD ◽  
E. D. WILLIAMS
Keyword(s):  
Human Calcitonin ◽  
Immunoradiometric Assay ◽  
C Cells ◽  
Green Fluorescence ◽  
Sandwich Technique ◽  
C Cell ◽  
Normal Rat ◽  
The Mean ◽  
Rat Thyroid ◽  
Mean Concentration

SUMMARY Immunolocalization techniques have been used to study 16 rat thyroids containing C cell tumours and ten rat thyroids in which no tumours or hyperplasias were found. All rats in these groups were at least 2 years old. An indirect ('sandwich') technique was used which involved rabbit or goat anti-human calcitonin antiserum and either fluorescein or peroxidase-labelled anti-rabbit or anti-goat IgG. Plasma calcitonin levels were measured in these animals and in a further group of ten young normal rats by means of an immunoradiometric assay using goat antiserum against synthetic human calcitonin. Both normal C cells and C cell tumours showed either apple-green fluorescence or positive peroxidase staining. The intensity of staining in the tumours varied from one cell to another but was in general less than that found for normal C cells. Calcitonin in the blood was detectable in most animals. The mean concentration found in young normal animals was 265 pg/ml (range < 100–600 pg/ml), in old normal animals 160 pg/ml (range < 100– 400 pg/ml) and in rats with small C cell tumours 470 pg/ml (range 100–1200 pg/ml). The mean concentration in this latter group differed significantly from those of both normal groups (P < 0·05). One animal with an invasive C cell tumour had a greatly increased calcitonin concentration (> 5 ng/ml) in the circulation. The results showed that calcitonin was present in normal rat C cells and that C cell tumours both contained and secreted calcitonin, underlining the similarity between these tumours and human medullary carcinomata.

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 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.

A TRANSIENT RISE OF HORMONE SECRETION: A RESPONSE OF THE STIMULATED RAT THYROID GLAND TO SMALL INCREMENTS OF IODIDE SUPPLY

1976 ◽  
Vol 81 (2) ◽  
pp. 507-515 ◽  
Author(s):  
H. Studer ◽  
H. Bürgi ◽  
H. Kohler ◽  
M. C. García ◽  
G. Morreale de Escobar
Keyword(s):  
Hormone Secretion ◽  
Transient Rise ◽  
Thyroid Glands ◽  
Tsh Secretion ◽  
The Face ◽  
Final Adjustment ◽  
Small Increments ◽  
Rat Thyroid ◽  
Rat Thyroid Gland ◽  
Serum Tsh

ABSTRACT Small doses of iodide (2 times 3.2 μg at 12 h interval), below those capable of inducing Wolff-Chaikoff effect, were injected into rats kept on a moderately low iodine diet. By means of a 125I equilibration technique as well as by direct measurement of cold T4, it was demonstrated that the level of circulating PB125I (representing iodothyronines as confirmed by column chromatography) increased by a mean of 40% within 24 h following the first iodide injection. The serum TSH concentration (measured by radioimmunoassay) was simultaneously depressed. Thus, in stimulated thyroid glands, a biologically significant fraction of an iodide load escapes autoregulatory control of iodothyronine synthesis. A small, transient increase of hormone release is likely to represent the physiological response of a normal gland to a sudden supplement of iodide supply. The ensuing depression of TSH secretion may be necessary for final adjustment of thyroid function. It is considered to be the last step in a cascade of mechanisms whose interaction keeps the thyroidal hormone output within narrow limits in the face of a fluctuating iodide supply. Failure of one or several of these mechanisms in the goitrous human gland could conceivable explain the phenomenon of "Jod Basedow".

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