Acute Increase of Thyroid Hormone Secretion in Response to Cold and Its Inhibition by Drugs which Act on the Autonomic or Central Nervous System

Kotani, Masanobu; Onaya, Toshimasa; Yamada, Takashi

doi:10.1210/endo-92-1-288

Cited by 42 publications

(18 citation statements)

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“…On the contrary, an effect of L-dopa and/or its metabolites directly at the pituitary level must be considered when taking into account that chronic treatment with L-dopa succeeds in inhibiting the TSH response to TRH [Spaulding et al, 1972], Finally, another possible action site of the catecholamine precursors could be the hypophysiotropic area of the hypothalamus. In fact, it is well-known that a large number of peptidergic neurons containing releasing or inhibiting factors are regulated by aminergic neurons [Wurtman, 1971], In terms of TRH-TSH secretion, the same evidence in the literature [Kotani et al, 1973] suggests a stimulatory role of central norepinephrinergic neurons on the activity of the hypothalamic-pituitary-thyroid axis. Such a catecholaminergic stimulatory effect might account for the stimulatory phase of the TSH response to L-dopa in our study.…”

Section: Discussionmentioning

confidence: 94%

Effect of L-Dopa on Plasma TSH Levels in Primary Hypothyroidism

Minozzi¹,

Faggiano²,

Lombardi³

et al. 1975

Neuroendocrinology

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Plasma TSH responses after an i.v. injection of 100 mg of L-dopa were evaluated by radioimmunoassay in 4 normal euthyroid subjects and in 8 patients with primary hypothyroidism. In agreement with previous results, no variations in plasma TSH levels were observed in the euthyroid subjects. In contrast, in primary hypothyroidism L-dopa induced a biphasic response in plasma TSH. In fact, we observed a transitory increase with a maximum at 30 min (mean ± SEM = 54 ± 18%) followed by a decrease reaching a minimum level of plasma TSH basal values at 90 min (mean ± SEM = 15 ± 6%). These findings demonstrate that the plasma TSH response to L-dopa in primary hypothyroidism is time-dependent. Some speculation on the possible mechanism of this action is presented.

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Section: Discussionmentioning

confidence: 94%

Effect of L-Dopa on Plasma TSH Levels in Primary Hypothyroidism

Minozzi¹,

Faggiano²,

Lombardi³

et al. 1975

Neuroendocrinology

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“…1972;Kotani et al, 1973], the present studies were designed to elucidate the role of brain biogenic amines in the control of this axis, using drugs which would augment or inhibit the synthesis of brain biogenic amines [Donoso et al. 1971[Donoso et al.…”

Section: Discussionmentioning

confidence: 99%

“…Animals were killed 30 min after exposure to cold (4°C). The thyroids were cleanly dis sected out and intrathyroidal colloid droplets were stained as reported previously [Onaya et al, 1969], The number of intrathyroidal colloid droplets per 25 follicles was counted to assess the activity of the hypothalamo-pituitary-thyroid axis in response to exposure to cold [Kajihara et al, 1972;Kotani et al, 1973;Montoya et al, 1975], Synthetic TRH was dissolved in saline and injected s.c. The drugs used in the present investigation were the following: sodium dicthyldithiocarbamate (DDC) (Nakarai Chemicals) and DL-alphamethyl-para-tyrosine methylester HC1 (a-MT) (Sigma) w'ere employed to block the syn thesis o f NE [Carlsson et al, 1966] and of catecholamines [Spector et al, 1965], respec tively.…”

Section: Methodsmentioning

confidence: 99%

Effects of Drugs That Modify Brain Biogenic Amine Concentrations on Thyroid Activation Induced by Exposure to Cold

Onaya¹,

Hashizume²

1976

Neuroendocrinology

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L-Dihydroxyphenylalanine (L-DOPA)significantly inhibited intrathyroidal colloid droplet formation induced by exposure to cold in the rat. Diethyldithiocarbamate (DDC) also inhibited colloid droplet formation in response to cold. The combined administration of L-DOPA and DDC produced an additive inhibition of the thyroidal endocytotic response to exposure to cold. Pretreatment with chlorpromazine (CPZ) ameliorated the inhibitory effect of (L-DOPA)DL-alpha-methyl-p-tyrosine (α-MT) also significantly depressed the thyroidal response. Inhibition of colloid droplet formation induced by α-MT was not altered by the administration of DL-dihydroxyphenylserine (DL-DOPS). On the other hand, treatment of the α-MT-treated rats with L-DOPA to normalize dopamine synthesis resulted in a dramatic recovery from the inhibition. Blockade of serotonin biosynthesis with p-chlorophenylalanine (p-CPA) failed to produce a significant inhibition of colloid droplet formation. However, 5-hydroxytryptophan (5-HTP) markedly inhibited the thyroidal response to cold. Brocresine phosphate (BP) was another inhibitor of the thyroidal endocytotic response to exposure to cold. Oxotremorine also markedly depressed the thyroidal response to cold. Since these drugs did not interfere with pituitary-thyroid responsiveness to exogenous thyrotropin-releasing hormone (TRH), it seems that the thyroidal endocytotic response to exposure to cold as a reflection of TSH secretion was directly influenced by alterations of brain biogenic amine concentrations or turnover rates.

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“…In studies on pinealectomized and corresponding control animals, the adaptation period was 3-4 days. The warmth adaptation was utilized to enhance the TSH cold response, as described by Kotani et al [13] and Tuomisto et al [29], The rats were given tap water and fed standard laboratory pellets (iodine content 0.5-1 mg/kg) ad libitum. The animals were killed in the afternoon between noon and 2 p.m. A part of the pinealectomized and corre sponding control rats were killed at midnight (pineal active) between 11.30 p.m. and 0.30 a.m. All noxious stimuli were avoided during the warmth-adaptation period and the exper iments.…”

Section: Animals and Housingmentioning

confidence: 99%

Complex Role of 5-HT in the Regulation of TSH Secretion in the Male Rat

Mattila¹,

Männistö²

1981

Horm Res

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The role of 5-hydroxytryptamine (5-HT) in the regulation of TSH secretion was studied in male rats using both peripheral and central administration of the drugs. Basal TSH levels were not modified by moderate doses of 5-HT (subcutaneously) or its precursors or antagonists (intraperitoneally) given 1 h before decapitation. The cold-stimulated TSH secretion was decreased by L-tryptophan (L-TRP, 400 mg/kg i.p.), quipazine (10 mg/kg i.p.) and 5-HT (1 or 5 mg/kg s.c. or i.v.) as well as by p-chlorophenylalanine (pCPA, 20 or more mg/kg i.p.) when the drugs were given 1 h before sampling. pCPA (100–400 mg/kg i.p.) was active 24-48 h after the injection but repetitive administration did not affect TSH levels. 5-HT (5 mg/kg s.c.) was effective also in pinealectomized animals. L-TRP and 5-hydroxytryptophan potentiated the TRH-stimulated TSH secretion when given 1 h before killing. 5-HT (10 µg/rat) infused into the third ventricle enhanced the cold-stimulated TSH secretion when given 30-45 min before sampling. When injected into the medial basal hypothalamus, 5-HT (1-10 µg/rat) had no effect on basal or stimulated TSH levels. The results suggest: (1) 5-HT does not play any role in the regulation of basal TSH secretion; (2) in the cold-stimulated TSH secretion 5-HT has a stimulatory action evidently inside the blood-brain barrier and also an inhibitory effect obviously outside this barrier.

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Acute Increase of Thyroid Hormone Secretion in Response to Cold and Its Inhibition by Drugs which Act on the Autonomic or Central Nervous System

Cited by 42 publications

References 0 publications

Effect of L-Dopa on Plasma TSH Levels in Primary Hypothyroidism

Effect of L-Dopa on Plasma TSH Levels in Primary Hypothyroidism

Effects of Drugs That Modify Brain Biogenic Amine Concentrations on Thyroid Activation Induced by Exposure to Cold

Complex Role of 5-HT in the Regulation of TSH Secretion in the Male Rat

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