Effect of cooling on intracellular transport and secretion of thyroglobulin

Ring, P.; Björkman, Ulla; Ekholm, R.

doi:10.1007/bf00215743

Cited by 9 publications

(3 citation statements)

References 33 publications

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“…These data suggest that newly synthesized thyroglobulin containing 3H-leucine did not accumulate in the colloid and together with thyroxin and triiodothyronine was released from thyrocytes under the effect of neurohormones. Similar dynamics of the formation and release of thyroglobulin was previously observed during in vitro action of thyrotropin [ 13]. Incubation of TG fragments in a medium containing OT and 3H-leucine increased the height of thyrocytes on the 30th and 60th minutes (6.34+0.67 and 7.8+0.56 vs. 5.19• and 5.26:60.14 ~ in the controls, respectively, p<0.05).…”

Section: Resultssupporting

confidence: 79%

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Norepinephrine-induced inhibition of thyroid-stimulating effects of oxytocin in rats

Makina

Krasnovskaya

1999

Bull Exp Biol Med

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In vivo and in vitro experiments on rats and isolated fragments of the thyroid gland showed 3H-oxytocin incorporation into thyrocytes followed by activation of the synthesis and release of thyroid hormones. Norepinephrine in vivo activates the thyroid gland, but combined action of norepinephrine and oxytocin suppressed in vivo and in vitro thyroid-stimulating effects of oxytocin. Key Words: thyroid gland; oxytocin; epinephrineVarious stress factors increase blood content of some hormones, responsible for the reaction to specific and nonspecific stress components. The increase in blood concentrations of catecholamine neurohormones of the adrenal medulla, epinephrine and norepinephrine (NE), is the major component of the hormonal reaction to stress. Hypothalamic nonapeptide hormones vasopressin and oxytocin (OT) are also released into the blood under the effect of various factors [4][5][6][7]. In light of this, combined effects of various neurohormones on target organs during stress are of considerable interest. In our previous experiments, we studied the reactions of rat thyroid gland (TG) in vivo [1] and thyrocytes in vitro [8] to combined action of vasopressin and epinephrine. However, there are no published data on the effects of combined treatment with OT and NE on mammalian TG. MATERIALS AND METHODSExperiments were performed on adult male Wistar rats weighing 140-160 g.In in vivo experiments, neurohormones and their combination were injected intraperitoneally 30 rain Laboratory of Neuroendocrinology, I. M. Sechenov Institute of Evolutional Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg before decapitation. The animals were divided into 4 groups (n=5) and injected with 1 ml physiological saline (control), 15 ng/100 g body weight OT, 30 ng/ 100 g body weight NE, and OT and NE in the same doses, respectively.After decapitation, TG was refnoved, fixed in Bouin's fluid, and subjected to routine histological treatment. The height of thyrocytes was measured on slices stained with azan by Heidenhain's method (x900).In vitro experiments were performed on 20 rats. Cross-sections (400 /.t) from the central zone of TG lobes were incubated in medium 199M saturated with carbogen (95% 02 and 5% CO2) at 37~ The medium was changed every 30 min. After 90-rain preincubation, the slices were transferred into the medium containing test neurohormones (60 min). We analyzed 5 groups of TG fragments incubated in media containing various neurohormones (100 pg/ml 3H-OT, 100 pg/ ml OT, 10 pM NE hydrotartrate, or both neurohormones in the same concentrations) or without neurohormones (control).All samples (except for those incubated with 3H-OT) were initially incubated in the medium containing 3H-leucine for 30 min. Some slices were then transferred into the medium without 3H-leucine, and others were further incubated with 3H-leucine. This method allows to assess the dynamics of thyroglobulin formation in thyrocytes and to determine the intensity of its transfer into the colloid or release from follicles [3,12,1...

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Section: Resultssupporting

confidence: 79%

“…Some slices were then transferred into the medium without 3H-leucine, and others were further incubated with 3H-leucine. This method allows to assess the dynamics of thyroglobulin formation in thyrocytes and to determine the intensity of its transfer into the colloid or release from follicles [3,12,13]. …”

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confidence: 99%

Norepinephrine-induced inhibition of thyroid-stimulating effects of oxytocin in rats

Makina

Krasnovskaya

1999

Bull Exp Biol Med

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“…Although the exact mechanism for the action of this drug still remains to be clarified, the interaction of BFAwith ER membranesto bring about was not determined in parotid acinar cells following IPR treatment, it should be emphasized that some, though not necessarily all, cis and, probably, medial elements continue to remain in the rudimentary form of Golgi complexes throughout the period of examination, and that they apparently becomespecial sites for Golgi complexreconstruction at the stage of recovery. Inhibition of the departure of materials from the RERhas been observed under various conditions such as low temperature (23,24,27) and inhibition of ATP production (12,27). According to Featherstone et al (7), the transport of newly synthesised G-protein of the vesicular stomatitis virus to the Golgi complexes from Fig.…”

Section: Discussionmentioning

confidence: 99%

Morphological effects of Brefeldin A on the intracellular transport of secretory materials in parotid acinar cells.

Yamashina

Katsumata

Tamaki

et al. 1990

Cell Struct. Funct.

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Key words: Golgi complex/Brefeldin A/parotid gland/secretion/electron microscopy ABSTRACT. The morphological effects of Brefeldin A (BFA) on the parotid acinar cells of a rat were investigated at the stage of active resynthesis of secretory materials following administration of the secretogogue, isoproterenol. Incubation with BFAresulted in: a) marked dilation of the rough endoplasmic reticulum (RER), b) involution of the Golgi complex to rudimentary forms which disseminated throughout the cytoplasm, and c) agenesis of secretion granules. It appears that the primary action of BFAis inhibition of the export of secretory materials from the RER toward the Golgi complexes. Histochemical staining indicated the thiamine pyrophosphatase (TPFase) positive saccules of the Golgi stack to undergo degradation in autophagic vacuoles. In contrast, small vesicles showing the osmiumreducing activity characteristic of cis elements, including osmium negative vesicles, continued to be present throughout a 4-h period of investigation, indicating the cis and, most likely, medial elements to be the components of the rudimentary Golgi complexes. On removal of the drug, a large number of transport vesicles appeared immediately from the RERand carried secretory materials to the rudimentary Golgi complex, so that the organdies were rapidly reconstructed within 30-60 min, followed by the reaccumulation of secretory granules by 90 min. It is thus indicated that the size and configuration of the Golgi complex is regulated by a dynamic equilibrium of the transport of secretory materials, and that the rudimentary Golgi complex containing cis and probably medial elements may function as the smallest units of the Golgi complex for full development as seen under normal conditions.

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Localization of the incorporation of 3H-galactose and 3H-sialic acid into thyroglobulin in relation to the block of intracellular transport induced by monensin

1987

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The Na+/K+ ionophore monensin is known to arrest the intracellular transport of newly synthesized proteins in the Golgi complex. In the present investigation the effect of monensin on the secretion of 3H-galactose-labeled and 3H-sialic acid-labeled thyroglobulin was studied in open thyroid follicles isolated from porcine thyroid tissue. Follicles were incubated with 3H-galactose at 20 degrees C for 1 h; at this temperature the labeled thyroglobulin remains in the labeling compartment (Ring et al. 1987a). The follicles were then chased at 37 degrees C for 1 h in the absence or presence of 1 microM monensin. Without monensin substantial amounts of labeled thyroglobulin were secreted into the medium, whereas in the presence of the ionophore secretion was inhibited by 80%. Since we have previously shown (Ring et al. 1987b) that monensin does not inhibit secretion of thyroglobulin present on the distal side of the monensin block we conclude that galactose is incorporated into thyroglobulin on the proximal side of this block. Secretion was also measured in follicles continuously incubated with 3H-galactose for 1 h at 37 degrees C in the absence or presence of monensin. In these experiments secretion of labeled thyroglobulin was inhibited by about 85% in the presence of monensin. Identically designed experiments with 3H-N-acetylmannosamine, a precursor of sialic acid, gave similar results, i.e., almost complete inhibition of secretion of labeled thyroglobulin in the presence of monensin. The agreement between the results of the galactose and sialic acid experiments indicates that sialic acid, like galactose, is incorporated into thyroglobulin on the proximal side of the monensin block.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effect of cooling on intracellular transport and secretion of thyroglobulin

Cited by 9 publications

References 33 publications

Norepinephrine-induced inhibition of thyroid-stimulating effects of oxytocin in rats

Norepinephrine-induced inhibition of thyroid-stimulating effects of oxytocin in rats

Morphological effects of Brefeldin A on the intracellular transport of secretory materials in parotid acinar cells.

Localization of the incorporation of 3H-galactose and 3H-sialic acid into thyroglobulin in relation to the block of intracellular transport induced by monensin

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