Effects of sodium on iodide transport in primary cultures of turtle thyroid cells

1986 ◽  
Vol 250 (4) ◽  
pp. E464-E469
Author(s):  
S. Y. Chow ◽  
Y. C. Yen-Chow ◽  
H. S. White ◽  
D. M. Woodbury
Keyword(s):  
Atpase Activity ◽  
Transport System ◽  
Cultured Cells ◽  
Primary Cultures ◽  
Transport Processes ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Iodide Transport ◽  
Cotransport System ◽  
K Activity

Iodide uptake by primary cultures of turtle thyroid cells decreased linearly with reduction of Na+ concentration in the medium, but changes in medium Cl- concentration did not affect iodide uptake. Ouabain, furosemide, monensin, and perchlorate all decreased 125I-uptake by cultured thyroid cells, whereas amiloride and triamterene did not. Ouabain, monensin, perchlorate, and amiloride depolarized the membrane of cultured cells, whereas furosemide and triamterene had no effect. Ouabain and perchlorate increased intracellular Na+ and Cl- and decreased K+ activities; furosemide and monensin reduced all three ions, but triamterene had no effect. Amiloride decreased intracellular Na+ and increased intracellular Cl- activities, however, its effect on K+ activity could not be determined because of interference by this compound of the K+ ion exchanger. All the agents, except furosemide, inhibited Na+-K+-ATPase activity. These experiments demonstrate that 1) Na+-I- cotransport is responsible for most iodide accumulation in thyroid cells; 2) Na+-I- cotransport system is linked to the Na+-K+ pump; 3) active iodide transport does not always correlate with Na+-K+-ATPase activity; 4) a perchlorate-sensitive iodide transport system is present in thyroid cells; 5) transport processes, not involved in active iodide transport (Na+-Cl- cotransport and Na+-H+ counter transport), are also present in cultured thyroid cells.

Effects of 4,4′-di-isothiocyano-2,2′-stilbene disulphonate on iodide uptake by primary cultures of turtle thyroid follicular cells

1987 ◽  
Vol 113 (3) ◽  
pp. 403-412 ◽  
Author(s):  
S. Y. Chow ◽  
Y. C. Yen-Chow ◽  
H. S. White ◽  
D. M. Woodbury
Keyword(s):  
Cultured Cells ◽  
Primary Cultures ◽  
Thyroid Tissue ◽  
Concentration Addition ◽  
Thyroid Cell ◽  
Follicular Cells ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Thyroid Follicular Cells ◽  
Cell Medium

ABSTRACT Iodide uptake by primary cultures of turtle thyroid follicular cells is directly proportional to the Na + concentration and is inversely proportional to the HCO3− concentration in culture medium, but is not affected by the Cl− concentration. Addition of 4,4′-di-isothiocyano-2,2′-stilbene disulphonate (DIDS; 10 μmol/l and higher doses) to medium containing different concentrations of Na+ (5–140 mmol/l), HCO3− (0–40 mmol/l) and Cl − (120 mmol/l) generally enhanced iodide uptake by the cultured cells; however, there was no significant effect in Na+-free and in low Cl− (90 mmol/l and less) medium. The inhibitory effects on iodide uptake of ouabain, frusemide and perchlorate were attenuated by DIDS which also antagonized the stimulatory effects on iodide uptake of TSH, although both DIDS and TSH increased the 125I− cell/medium ratio when they were given alone. At doses of 100 μmol/l and higher, DIDS lowered the intracellular pH of cultured cells when the pH of the medium was maintained at a constant level. It also increased the intracellular Cl − concentration, but had no effect on intracellular Na+ or K +. The input and specific resistances of cell membranes in cultured thyroid cells and in isolated thyroid slices increased (decreased conductance) after adding DIDS to the perfusion fluids. Both Na+/K+- and HCO3−-ATPase activities in homogenates of turtle thyroid tissue were inhibited by DIDS. Results from this investigation demonstrate (1) that in addition to preventing the leak of iodide from thyroid cells, DIDS may act to increase the sensitivity of the Na + -anion carrier to I− and thereby increases iodide uptake, and (2) that a HCO3−–Cl− exchange system is present in the thyroid cell membrane and appears to be linked to the transport of iodide into thyroid cells. J. Endocr. (1987) 113, 403–412

An investigation of the optimum culture conditions for a differentiated culture of sheep thyroid cells

1983 ◽  
Vol 104 (4) ◽  
pp. 431-436 ◽  
Author(s):  
Ann Murphy ◽  
Carmel Mothersill ◽  
M. K. O'Connor ◽  
J. F. Malone ◽  
M. J. Cullen ◽  
...  
Keyword(s):  
Culture System ◽  
Primary Cultures ◽  
Cell Number ◽  
Culture Conditions ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
System A ◽  
Thyrotrophic Hormone ◽  
A Cell ◽  
The Media

Abstract. Primary cultures of differentiated sheep thyroid were investigated to assess the effect of varying the media, sera, hormones and the initial cell number plated on the culture life span. Iodide uptake and follicular morphology were used as indices of differentiation. It was found that the effect of variations in the type of medium and the concentration and type of serum used was very small. The addition of all the hormones used – insulin, hydrocortisone and thyrotrophic hormone – had a synergistic effect on the iodide trapping ability of the culture system. A cell number of approximately 1 × 106 cells per 25 cm2 flask was found to be optimum for the development of differentiation in the cultures.

Relation between pH regulation and iodide transport in turtle thyroid glands

1990 ◽  
Vol 127 (1) ◽  
pp. 85-101 ◽  
Author(s):  
S. Y. Chow ◽  
D. M. Woodbury ◽  
Y. C. Yen-Chow
Keyword(s):  
Thyroid Gland ◽  
Transport System ◽  
Ph Regulation ◽  
Exchange Process ◽  
Control Level ◽  
Regulatory System ◽  
Transport Processes ◽  
Iodide Transport ◽  
Cell Ph ◽  
Thyroid Glands

ABSTRACT Mechanisms of pH recovery after alkalinization and acidification by exposing or prepulsing turtle thyroid slices with a Hanks' balanced salt solution (HBSS) containing NH4Cl or CO2 were studied by examining the effects of amiloride, 4-acetamido-4′-isocyanostilbene-2,2′-disulphonic acid (SITS), frusemide and acetazolamide, and of reducing the concentration of Na+ or Cl− in the incubation medium. When alkalinization was produced either during exposure to NH4Cl or after a CO2 pulse, the pH in thyroid slices rose rapidly and then recovered gradually. Addition of SITS (0·1 mmol/l) or reduction of the Cl− concentration markedly inhibited pH recovery. However, amiloride (0·1 mmol/l) and low Na+ in the medium had no significant effect on recovery from alkalinization induced by NH4Cl exposure or by a CO2 pulse. These data suggest that pH recovery from alkalinization in turtle thyroid gland is achieved by an exchange of internal HCO3− for external Cl−. When acidification was accomplished by either exposure to CO2 or removal of NH4Cl, the pH of thyroid slices fell rapidly and then recovered gradually. If amiloride was added or the Na+ concentration in the medium was reduced, the pH recovery was greatly attenuated. However, SITS and low Cl− in the medium did not affect the recovery from an acid load in turtle thyroid slices. These results suggest that pH recovery from acidification in turtle thyroid gland is achieved by an exchange of internal H+ for external Na+. Both frusemide and acetazolamide prevented the pH recovery in turtle thyroid slices during exposure to and withdrawal from NH4Cl. These results suggest that besides the Na+-H+ and Cl−-HCO3− exchange processes, other mechanisms may also be involved in pH regulation in turtle thyroid glands. Simultaneous uptakes into turtle thyroid slices of 125I− and 22Na+ and of 125I− and 36Cl− were studied during and following exposure to NH4Cl in the absence and presence of different transport inhibitors, such as frusemide, amiloride, SITS and acetazolamide. When the thyroid slices were exposed to HBSS containing 30 mmol/l NH4Cl (alkalinization phase), the tissue/medium (T/M) ratios of 125I− increased gradually, reached the highest point in 10 min, and were maintained at this level for the next 20 min. The T/M ratios of 22Na+ and 36Cl− of thyroid slices also slowly increased after exposure to NH4Cl. After withdrawal of NH4Cl (acidification phase), the T/M ratios of 125I− decreased rapidly below the control level (samples not exposed to NH4Cl), reached the lowest point in 2–5 min, and returned to the control level within 20–30 min. During the withdrawal period, the T/M ratios of 22Na+ were either not changed or slightly increased further; the T/M ratios of Cl− were not changed; and the T/M ratios of both 22Na+ and 36Cl− were higher than the controls. Frusemide decreased the T/M ratios of 125I−, 22Na+ and 36Cl− in both the alkalinization and acidification phases. Amiloride decreased the T/M ratios of both 125I− and 22Na+ only in the acidification phase, but had no effect on the T/M ratios of 36Cl− in both the alkalinization and acidification phases. SITS increased the T/M ratios of 125I−, but slightly decreased the T/M ratios of 36Cl− in the alkalinization phase. It had no effect on the T/M ratios of 36Cl− in the acidification phase, nor on the T/M ratios of 22Na+ in both the alkalinization and acidification phases. Acetazolamide increased the T/M ratios of 125I− and 36Cl− in both the alkalinization and acidification phases, and had no effect on the uptake of 22Na+ by the thyroid slices in both phases. Based on the results of these studies, it appears likely that under normal conditions or when cell pH is lower than normal, the Na+-dependent I− transport system acts in concert with the Na+-H+ exchange and the Na+-HCO3− co-transport processes of the pH regulatory system to maintain the accumulation of I− and to increase the pH inside thyroid follicles. When cell pH is higher than normal, the Na+-dependent I− transport system acts in concert with the Cl−-HCO3− exchange process of the pH regulatory system to enhance the accumulation of I− and to decrease the pH in thyroid glands. Journal of Endocrinology (1990) 127,85–101

Role of 3′, 5′ cyclic adenosine monophosphate and protein kinase C in the regulation of insulin-like growth factor-binding protein secretion by thyroid-stimulating hormone in isolated ovine thyroid cells

1994 ◽  
Vol 141 (2) ◽  
pp. 231-242 ◽  
Author(s):  
J F Wang ◽  
D J Hill ◽  
G P Becks
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Primary Cultures ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Thyroid Cell ◽  
Dibutyryl Camp ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Kinase C

Abstract Isolated sheep thyroid follicles release insulin-like growth factors (IGF)-I and -II together with IGF-binding proteins (IGFBPs). We previously showed that TSH suppresses the biosynthesis and release of IGFBPs in vitro which may increase the tissue availability of IGFs, allowing a synergy with TSH which potentiates both thyroid growth and function. Many of the actions of TSH on thyroid cell function are dependent upon activation of adenylate cyclase, although increased synthesis of inositol trisphosphate and activation of protein kinase C (PKC) have also been implicated. We have now examined whether probable changes in intracellular cyclic adenosine monophosphate (cAMP) or PKC are involved in TSH-mediated suppression of IGFBP release. Confluent primary cultures of ovine thyroid cells were maintained in serum-free Ham's modified F-12M medium containing transferrin, somatostatin and glycyl-histidyl-lysine (designated 3H), and further supplemented with sodium iodide (10−8–10−3 mol/l), dibutyryl cAMP (0·25–1 mmol/l), forskolin (5–20 μmol/l) or 12-0-tetradecanoylphorbol-13-acetate (TPA; 10−11–10−6 mol/l), with or without exposure to TSH (200 μU/ml). The uptake and organification of Na [125I] by cells was examined after test incubations of up to 48 h, and IGFBPs in conditioned media were analysed by ligand blot using 125I-labelled IGF-II. The PKC activity in the cytosol and plasma membrane fractions of cells was measured by phosphorylation of histone using [γ-32P]ATP, and PKC immunoreactivity was visualized by Western immunoblot analysis. While dibutyryl cAMP or forskolin largely reproduced the stimulatory effect of TSH on iodine organification, they did not mimic the inhibitory effect of TSH on the secretion of IGFBPs of 43, 34, 28 and 19 kDa. Incubation with physiological or pharmacological concentrations of iodide (10−6–10−3 mol/l) for up to 48 h significantly decreased TSH action on iodide uptake and organification but did not alter the inhibitory action of TSH on IGFBP release. Incubation of cells with 10−11–10−6 mol TPA/l for 24 h inhibited the subsequent ability of TSH both to potentiate iodine organification and to suppress IGFBP release. In 3H medium, PKC activity was predominantly recovered from the membrane fraction but, following incubation for 48 h with TSH, the enzyme was no longer translocated to the membrane and was recovered predominantly from the cytosol. An 80 kDa species of immunoreactive PKC was recovered from the membranes of cells cultured in 3H medium, but its presence in membrane was decreased following incubation with TSH. The actions of TSH on intracellular PKC distribution were reversed by prior incubation with TPA, which itself stimulated the appearance of membrane PKC immunoreactivity. These results suggest that the ability of TSH to suppress IGFBP release does not depend primarily on cAMP stimulation, but may involve changes in the activation of PKC, possibly inhibition or down-regulation. Journal of Endocrinology (1994) 141, 231–242

Role of sodium influx in thyrotrophin action: effects of the sodium channel agonist veratridine and thyrotrophin on radioiodine turnover and membrane potential in cultured porcine thyroid cells

1986 ◽  
Vol 110 (3) ◽  
pp. 459-466 ◽  
Author(s):  
S. W. Manley ◽  
G. J. Huxham ◽  
J. R. Bourke
Keyword(s):  
Sodium Channel ◽  
Potassium Concentration ◽  
Exit Rate ◽  
Iodide Uptake ◽  
Sodium Influx ◽  
Thyroid Cells ◽  
Iodide Transport ◽  
Stimulation Of ◽  
Channel Agonist

ABSTRACT Veratridine, a sodium channel agonist, depolarized cultured thyroid cells and increased the secretion of radioiodine from the organically bound pool. These effects were similar to those of TSH. Depolarization of the cells by increasing the potassium concentration of the medium failed to promote secretion, indicating that the sodium influx, rather than the depolarization itself, mediated the response. Veratridine, like TSH, also acutely reduced the cells' iodide uptake and inhibited the iodide transport pump. Unlike TSH, however, veratridine reduced, rather than increased, the fractional exit rate of iodide anion from the unbound pool. The data are consistent with the hypothesis that a sodium influx mediates some but not all of the actions of TSH on the thyroid gland, including the stimulation of secretion of thyroid hormones. J. Endocr. (1986) 110, 459–466

Na+-H+ antiport and monensin effects on cytosolic pH and iodide transport in FRTL-5 rat thyroid cells

1992 ◽  
Vol 262 (6) ◽  
pp. E834-E839
Author(s):  
R. C. Smallridge ◽  
I. D. Gist ◽  
J. G. Kiang
Keyword(s):  
Maximum Velocity ◽  
Atp Depletion ◽  
High Dose ◽  
Iodide Uptake ◽  
Cytosolic Ph ◽  
Thyroid Cells ◽  
Iodide Transport ◽  
Sodium Dependent ◽  
Rat Thyroid ◽  
Ionophore Monensin

Na+-H+ exchange may proceed via an endogenous antiporter or by exposure to the Na+ ionophore monensin. We investigated the characteristics of Na+-H+ exchange induced by antiporter stimulation and by monensin in FRTL-5 rat thyroid cells. We also examined the effects of intracellular pH (pHi) changes on iodide uptake and efflux. pHi was determined using 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. The resting pHi was 7.33 +/- 0.02 units; this level correlated directly with extracellular pH. In acid-loaded cells, Km for external Na+ activation of the antiporter was 7.1 mM and maximum velocity was 0.3801 delta pH units/min. Dimethylamiloride was 42 times more potent than amiloride in inhibiting sodium-dependent recovery in acidified cells. Metabolic inhibition reduced the initial alkalinization rate. Monensin increased pHi, and this response was dependent on extracellular Na+ and HCO3- but not on antiporter function. Low-dose monensin (1 microM) and 1 mM NH4Cl enhanced 125I uptake. High-dose monensin (100 microM), but not NH4Cl, reduced iodide uptake. Neither NH4Cl nor monensin altered 125I efflux. Thus FRTL-5 cells possess an amiloride-sensitive Na+-H+ exchanger, which is not essential for maintaining basal pHi but is affected by ATP depletion. Monensin also alkalinizes these cells but independently of the antiporter. Iodide uptake, but not efflux, is affected by changes in intracellular Na+ and H+ levels.

scholarly journals MEK signaling modulates sodium iodide symporter at multiple levels and in a paradoxical manner

2007 ◽  
Vol 14 (2) ◽  
pp. 421-432 ◽  
Author(s):  
Douangsone D Vadysirisack ◽  
Anjli Venkateswaran ◽  
Zhaoxia Zhang ◽  
Sissy M Jhiang
Keyword(s):  
Cell Surface ◽  
Atpase Activity ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Sodium Iodide Symporter ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Thyroid Cancers ◽  
Protein Levels ◽  
Radioiodine Ablation

The Na+/I− symporter (NIS)-mediated iodide uptake is the basis for targeted radioiodine ablation of thyroid cancers. However, NIS-mediated radioiodide uptake (RAIU) activity is often reduced in thyroid cancers. As mitogen activated protein kinase (MAPK) signaling pathway is activated in about 70% of papillary thyroid carcinoma, we investigated whether MEK (MAPK kinase) inhibition will restore NIS protein levels and NIS-mediated RAIU activity in RET/PTC oncogene-transformed thyroid cells. We found that MEK inhibitor PD98059 increased NIS protein levels within 30 min of treatment. However, the increase of NIS protein level was not accompanied with an increase in NIS-mediated RAIU activity, particularly at early time points of PD98059 treatment. PD98059 also decreased RAIU activity mediated by exogenous NIS in non-thyroid cells. The transient decrease of RAIU activity by PD98059 in thyroid cells was not due to decreased NIS cell surface level, decreased NIS binding affinity for I− , or increased iodide efflux. While PD98059 moderately decreased Na+/K+-ATPase activity, ouabain titration indicates that the extent of decrease in Na+/K+-ATPase activity is much greater than the extent of decrease in RAIU activity. Additionally, a decrease of Na+/K+-ATPase activity was not accompanied with a decrease of biotin uptake activity mediated by Na+-dependent multivitamin transporter. Since PD98059 reduced Vmax− I− without decreasing NIS cell surface levels, it is most likely that PD98059 decreases the turnover rate of iodide transport with an yet to be identified mechanism.

A replica filter assay for expression of ion transport proteins

1991 ◽  
Vol 261 (4) ◽  
pp. C708-C712
Author(s):  
S. Obici ◽  
Q. al-Awqati ◽  
E. V. Avvedimento ◽  
M. E. Gottesman
Keyword(s):  
Ion Transport ◽  
Transport System ◽  
Transport Proteins ◽  
Transport Systems ◽  
Thyroid Cell ◽  
Intracellular Accumulation ◽  
Thyroid Cells ◽  
Cyclic Monophosphate ◽  
Iodide Transport ◽  
Filter Assay

In thyroid cells, iodide is accumulated intracellularly via a Na+-I-cotransporter. In this report we show that it is possible to detect diffusible 125I-concentrated in thyroid cell colonies that have been replicated onto nylon filters. Using the replica filter assay, we demonstrate that the iodide transport 1) is restricted to thyroid cells, 2) is Na+ dependent and electrogenic, 3) is inhibited by ClO4- and SCN-, and 4) is adenosine 3',5'-cyclic monophosphate dependent. These are all characteristics of thyroidal iodide transport. This technique can, in principle, detect the expression of any transport system that results in the intracellular accumulation of a diffusible molecule. Moreover, the filter assay can be used to screen for colonies carrying structural or functional mutations affecting such transport systems.

Hydrogen peroxide inhibits iodide influx and enhances iodide efflux in cultured FRTL-5 rat thyroid cells

1990 ◽  
Vol 122 (5) ◽  
pp. 610-616 ◽  
Author(s):  
Masahiro Sugawara ◽  
Dean T. Yamaguchi ◽  
Hsin Y. Lee ◽  
Kurumi Yanagisawa ◽  
Saburo Murakami ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Atpase Activity ◽  
Significant Inhibition ◽  
Transport Systems ◽  
Thyroid Cells ◽  
Major Mechanism ◽  
Iodide Transport ◽  
Presence And Absence ◽  
Rat Thyroid

Abstract. This study describes the effects of hydrogen peroxide on the two iodide transport systems, I− influx and I− efflux, in the cultured FRTL-5 rat thyroid cells. I− influx was measured by the amount of I− taken up by the cells during incubation with Na125I and NaI for 7 min, and I− efflux was measured by calculating the rate of 125I release from the 125I-loaded cells in the presence and absence of 5 mmol/l H2O2. Exposure to greater than 100 μmol/l H2O2 for 40 min caused a significant inhibition of I− influx; the inhibition was reversible and non-competitive with iodide. Thyroid Na+K+ATPase activity, a major mechanism to drive I− influx, decreased by 40% after the cells were exposed to 5 mmol/l H2O2 for 10 min. H2O2 enhanced I− efflux only when Ca2+ was present in the medium. The mechanism of an enhanced I− efflux by H2O2 appears to be mediated through the elevation of free cytosolic Ca2+ concentration. Our data indicate that H2O2 can affect I− transport by inhibiting I− influx and enhancing I− efflux.

Thyrotrophin and the differential expression of proliferation and differentiation in dog thyroid cells in primary culture

1983 ◽  
Vol 96 (2) ◽  
pp. 241-249 ◽  
Author(s):  
P. P. Roger ◽  
J. E. Dumont
Keyword(s):  
Cell Proliferation ◽  
Cyclic Amp ◽  
Stationary Phase ◽  
Primary Cultures ◽  
Latency Period ◽  
Iodide Uptake ◽  
Signal Molecule ◽  
Thyroid Cells ◽  
Proliferation And Differentiation ◽  
A Cell

Cell proliferation and the expression of differentiated functions are generally considered to be mutually exclusive states of the cell. Thyrotrophin activates the expression of differentiated functions in dog thyroid cells by means of cyclic AMP. We have recently shown that thyrotrophin also acts through the same intracellular signal molecule to enhance proliferation of dog thyroid cells in primary cultures. In this work we showed that such primary cultures exhibit three successive phases: a latency period during which the expression of differentiated functions (iodide trapping and organification) declined, the cells still being associated with structures derived from the seeded follicles; a cell-proliferation phase with little expression of these functions, the cells being spread in a monolayer; a stationary phase with cell density reaching a plateau but no re-expression of the functions. Thyrotrophin promoted proliferation during the multipli-cation phase, but induced redifferentiation during the stationary phase. These effects were mimicked by cholera toxin and dibutyryl cyclic AMP, which suggested that they were mediated by cyclic AMP. Iodide uptake was also stimulated by cortisol. Thyrotrophin therefore has a different action in dog thyroid cells depending on the state of the cells. The spontaneous arrest of multiplication appears to make the cells competent to respond to thyrotrophin by the induction of redifferentiation.

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