Iodothyronine Release from the Perfused Canine Thyroid following Cessation of Stimulation

Laurberg, Peter

doi:10.1172/jci109692

Cited by 22 publications

(7 citation statements)

References 19 publications

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“…The ratio of T3 to T4 on thyroglobulin increases in iodine deficiency, consistent with an effect of TSH on de novo hormone synthesis (Visser 1988). A further possibility is that enhanced thyroidal T3 production results from an increased activity of thyroidal ID-I acting on T4 (Green 1978, Laurberg 1980, 1984. Such a mechanism can only operate in man, rodents and dog since most other species do not express ID-I in the thyroid .…”

Section: Introductionmentioning

confidence: 68%

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

Beech

Walker²,

Arthur³

et al. 1995

Journal of Molecular Endocrinology

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The effects of TSH and the activation of the cyclic AMP (cAMP) and Ca(2+)-phosphatidylinositol (Ca(2+)-PI) cascades on the activity and expression of the selenoenzyme thyroidal type-I iodothyronine deiodinase (ID-I) have been studied using human thyrocytes grown in primary culture. Stimulation of ID-I activity and expression was obtained with TSH and an analogue of cAMP, 8-bromo-cAMP. In the presence or absence of TSH, the addition of the phorbol ester, phorbol 12-myristate 13-acetate (PMA) together with the calcium ionophore A23187, caused a decrease in ID-I activity; a decrease in ID-I expression was also observed as assessed by cell labelling with [75Se]selenite. PMA alone had no effect on ID-I activity in the presence or absence of TSH. A23187 alone produced a small but significant reduction in ID-I activity, but only in TSH-stimulated cells. These data provide evidence that the expression of thyroidal ID-I is negatively regulated by the Ca(2+)-PI cascade, and positively regulated by the cAMP cascade.

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Section: Introductionmentioning

confidence: 68%

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

Beech

Walker²,

Arthur³

et al. 1995

Journal of Molecular Endocrinology

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“…Effects of CCK-related peptides on calcitonin secretion Once-through perfusion of isolated thyroid lobes was performed in four mongrel dogs weighing 17-23 kg (Laurberg, 1980). In brief, each thyroid lobe was isolated in situ in such a way that perfusion medium pumped into an isolated segment of the common carotid artery could pass through the thy¬ roid lobe only, and be collected quantitatively through a catheter in the internal jugular vein.…”

Section: Methodsmentioning

confidence: 99%

Cholecystokinin peptides as local modulators of thyroidal calcitonin secretion in the dog?

Laurberg¹,

Jf²

1987

Journal of Endocrinology

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Cholecystokinin (CCK) is a heterogeneous gut hormone which is also synthetized in extra-intestinal endocrine cells and neurons. In order to examine the possibility that CCK peptides are local modulators of calcitonin secretion, we have studied the structure-activity relationship on calcitonin secretion from perfused canine thyroid lobes as well as the presence and molecular nature of CCK in the thyroid. Peptides containing the intact COOH-terminal tetrapeptide amide of CCK (CCK-4, CCK-5, pentagastrin, CCK-8 and gastrin-17) all induced dose-dependent (0.1, 3 and 100 nmol/l) increases in calcitonin release (P less than 0.05, n = 4) with biphasic secretion during 6-min infusion periods. The deamidated tetrapeptide and the COOH-terminal tripeptide were without effect. Gel chromatography of neutral water and acid-ethanol extracts of thyroid tissue, monitored by sequence-specific CCK and gastrin radioimmunoassays, disclosed a variety of CCK and gastrin peptides of which a predominant form resembled small molecular forms like CCK-4 and CCK-5. The presence in the thyroid of small CCK-like peptides and the pronounced effect of such peptides on calcitonin secretion suggest that calcitonin secretion is modulated by local release of small CCK peptides. They could originate from intrathyroidal nerves or from sub-populations of C-cells.

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“…Both triiodothyronine and reverse T3 origi¬ nated from thyroxine, in a fashion similar to that in rat (Haibach 1971;Green 1978;Erickson et al 1981), dog (Laurberg 1980) and human thyroid (Bidey et al 1976;Ishii et al 1980), as well as in many peripheral tissues (Chopra 1981). However, some differences between the thyroid and the other organs became evident when the influence of several agents on labelled thyroxine metabolism was examined.…”

Section: Discussionmentioning

confidence: 61%

Uptake, metabolism and subcellular distribution of [125I]T4 in calf thyroid slices

Chazenbalk

Pisarev

Juvenal

et al. 1984

Acta Endocrinologica

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Previous work from our laboratory has shown that iodothyronines have a direct inhibitory action on the thyroid. In the present studies the uptake, metabolism and subcellular distribution of labelled thyroxine were analyzed. The entry of this hormone reaches a plateau after 15\p=n-\20min incubation and is temperature-dependent. The T/M values for T4 were much lower than those of labelled T3 and the curve was different from that obtained with [125I]. The influence of a series of compounds on the T/M values for thyroxine was studied. KI, T3, IOP PTU and MMI were without effect. Absence of Ca++ in the buffer, or addition of KClO4 or ouabain caused a slight decrease, while TSH produced a stimulation in the T/M ratio. Calf thyroid slices dehalogenated thyroxine, producing both T3 and rT3. TSH increased the generation of these two compounds. Neither PTU nor IOP altered the production of T3 and rT3 significantly. The lack of effect of IOP on T3 and rT3 generation was confirmed in calf thyroid homogenates. However, and in agreement with previous reports, IOP significantly decreased production of both triiodothyronines in rat liver slices and in rat liver homogenates. When the subcellular distribution of labelled thyroxine was examined most of the radioactivity appeared in the soluble fraction and less than 1 % was present in purified nuclei. The addition of unlabelled thyroxine to the slices only caused a significant displacement in the radioactivity of purified nuclei. The presence of labelled thyroxine in the nuclei was confirmed by paper chromatography. lodine has been used for many years in the treat¬ ment of goitre and to relieve symptoms of Graves' disease. Many studies have been performed in order to clarify its mechanism of action (see reviews Wolff 1976; Pisarev & Kleiman de Pisarev 1980).

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Iodothyronine Release from the Perfused Canine Thyroid following Cessation of Stimulation

Cited by 22 publications

References 19 publications

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

Cholecystokinin peptides as local modulators of thyroidal calcitonin secretion in the dog?

Uptake, metabolism and subcellular distribution of [125I]T4 in calf thyroid slices

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