Hypersecretion of corticotrophin-releasing hormone and arginine vasopressin in hypothyroid male rats as estimated with push-pull perfusion

Tohei, Atsushi; Watanabe, Gen; Taya, Kazuyoshi

doi:10.1677/joe.0.1560395

Cited by 20 publications

(15 citation statements)

References 29 publications

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“…There are several factors which inhibit LHRH secretion, and CRH is one of major factors for inhibiting it [21][22][23]. In the present study, hypersecretion of CRH [24] was confirmed in hypothyroid rats. Deficits in gonadal function at the hypothalamic-pituitary levels in hypothyroid rats may be mediated at least, partly, by CRH.…”

Section: Functional Relationship Between Thyroid Gland and Hpg Axis Isupporting

confidence: 68%

“…Mos t o f the previo us reports rega rding the relationship between thyroid status and gonadal function only mentioned the direct effects of hypothyroidism on the HPG axis in female animals [4,[32][33][34]. The results from the present study suggest that hypothyroidism causes adrenal dysfunction directly and results in hypersecretion of ACTH in adult male rats [7,24]. The adrenal dysfunction, may contribute to the inhibition of LHRH secretion from hypothalamus, possibly m e d i a t e d b y e x ce ss C R H [ 7 , 2 4 ] .…”

Section: The Hpa and Hpg Axes In Hypothyroid Adult Female Ratsmentioning

confidence: 50%

“…In summary, hypothyroidism causes adrenal dysfunction and hyposecretion of corticosterone by the adrenal gland directly and results in the hypersecretion of CRH and AVP [7,24]. The site of dysfunction in gonadal axis is mainly at the hypothalamus-pituitary level [7,58] in hypothyroid m ale r ats , and t he dysfunctio n is pro bably mediated by endogenous CRH [7,24,59].…”

Section: Discussionmentioning

confidence: 99%

“…The site of dysfunction in gonadal axis is mainly at the hypothalamus-pituitary level [7,58] in hypothyroid m ale r ats , and t he dysfunctio n is pro bably mediated by endogenous CRH [7,24,59]. In female rats, hypothyroidism causes hyperprolactinemia, and result in prolonged diestrous period [47].…”

Section: Discussionmentioning

confidence: 99%

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Studies on the Functional Relationship between Thyroid, Adrenal and Gonadal Hormones

Tohei

2004

J. Reprod. Dev.

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Abstract. In order to clarify the functional relationship between thyroid, adrenal and gonadal hormones, hypothyroidism was induced by administration of thiuoracil in adult male and female rats, and the effects of hypothyroidism on the adrenal and the gonadal axes were investigated in the present study. 1. The functional relationship between thyroid and adrenal hormones: Adrenal weights and corticosterone were lowered, whereas the secretion of ACTH, corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) increased in hypothyroid rats compared to euthyroid rats. These results indicate that hypothyroidism causes adrenal dysfunction directly and results in hypersecretion of CRH and AVP from the hypothalamus. 2. The functional relationship between thyroid and gonadal hormones: The pituitary response to LHRH was lowered, whereas the testicular response to hCG was not changed in hypothyroid rats. Hypothyroidism suppressed copulatory behavior in male rats. These results suggest that hypothyroidism probably causes dysfunction in gonadal axis at the hypothalamic-pituitary level in male rats. In adult female rats, hypothyoidism inhibited the follicular development accompanied estradiol secretion, whereas plasma concentrations of progesterone and prolactin (PRL) increased in hypothyroid female rats. Hypothyroidism significantly increased the pituitary content of vasoactive intestinal peptide (VIP) though it did not affect dopamine synthesis. These results suggest that hypothyroidism increases pituitary content of VIP and this increased level of VIP likely affects PRL secretion in a paracrine or autocrine manner. In female rats, inhibition of gonadal function in hypothyroid rats mediated by hyperprolactinemia in addition to hypersecretion of endogenous CRH.

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Section: Functional Relationship Between Thyroid Gland and Hpg Axis Isupporting

confidence: 68%

Section: The Hpa and Hpg Axes In Hypothyroid Adult Female Ratsmentioning

confidence: 50%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Studies on the Functional Relationship between Thyroid, Adrenal and Gonadal Hormones

Tohei

2004

J. Reprod. Dev.

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“…The AVP content in the ME was measured using a commercial RIA k i t p u r c h a s e d f r o m M i t s u b i s h i C h e m i c a l Corporation (Tokyo, Japan) [31]. The intra-and interassay coefficients of variation for AVP were 6.9 and 11.2%, respectively.…”

Section: Radioimmunoassay (Ria)mentioning

confidence: 99%

Inhibition of Stress-Induced Adrenocorticotropin and Prolactin Secretion Mediating Hypophysiotropic Factors by Antagonist of AMPA Type Glutamate Receptor

Kusakawa

Tohei

Jaroenporn

et al. 2007

Journal of Reproduction and Development

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Abstract. Glutamate is the dominant excitatory neurotransmitter in a large number of physiological processes including neuroendocrine regulation. Some pharmacological studies have shown that different subtypes of glutamate receptor, such as the N-methyl-D-aspartic acid (NMDA) and α-amino-3-hydroxy-5-methy-4-isoxazolepropionic acid (AMPA) receptors, are involved in stress-induced adrenocorticotropin (ACTH) and prolactin secretion. However, the roles of the respective glutamate receptors and the mechanism of ACTH and prolactin secretion during stress via these receptors have not been investigated in detail. In the present study, we evaluated the role of AMPA-type glutamate receptor in ACTH and prolactin regulation under restraint stress in adult male rats. Male rats pretreated with a selective AMPA receptor antagonist, 2, 3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX; 50 µg), through a lateral ventricle cannula were stressed by immobilization. Administration of NBQX inhibited ACTH and prolactin secretion in response to restraint stress. However, NBQX had no significant effects on the activity of tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis, as measured by the accumulation of 3, 4-dihydroxyphenylalanine (DOPA). In addition, administration of NBQX suppressed stress-induced prolactin secretion in the male rats pretreated with α-MT, an inhibitor of dopamine synthesis, and infused with dopamine solution (2.5 µg/200 µl/10 min). These results indicated that the effects of NBQX on prolactin secretion might be mediated by non-dopamine mechanisms. The contents of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) in the median eminence (ME) of the male rats decreased during restraint stress; however, the fluctuations in CRH and AVP were eliminated by NBQX administration. These results suggest that stress-induced ACTH and prolactin release mediated by neurotransmission via AMPA receptors might be partly attributable to hypophysiotropic regulatory factors in the hypothalamus. Key words: Adrenocorticotropin (ACTH), α-Amino-3-hydroxy-5-methy-4-isoxazolepropionic acid (AMPA), Prolactin, Rat, Stress (J. Reprod. Dev. 53: [545][546][547][548][549][550][551][552][553][554] 2007) he excitatory amino acid glutamate is the primary mediator of excitatory synaptic transmission in the central nervous system [1,2].

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Effects of short- and long-duration hypothyroidism on hypothalamic–pituitary–adrenal axis function in rats: In vitro and in situ studies

et al. 2012

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The purpose of this study is to assess the effects of hypothyroidism on the hypothalamic-pituitary-adrenal (HPA) axis; the functional integrity of each component of the HPA axis was examined in short-term and long-term hypothyroidism. Neuropeptide synthesis, release, and content were evaluated in vitro both in the hypothalamus and anterior pituitary, and corticosterone release was assessed in primary adrenal cell cultures at 7 (short-term) and 60 days (long-term hypothyroidism) after thyroidectomy in male rats. Hypothyroid rats showed adrenal insufficiency in several parameters, which were associated with the duration of hypothyroidism. Cerebrospinal (CSF) ACTH was decreased in all hypothyroid animals, while CSF corticosterone levels were significantly decreased only in long-term hypothyroidism. Long-term hypothyroid animals showed decreased corticotropin-releasing hormone (CRH) mRNA expression in the hypothalamic paraventricular nucleus under both basal and stress conditions, decreased CRH release from hypothalamic organ cultures after KCL and arginine vasopressin stimulation, as well as an increased number of anterior pituitary CRH receptors. In contrast, short-term hypothyroid rats showed changes in anterior pituitary function with an increased responsiveness to CRH that was associated with an increase in CRH receptors. Although both short- and long-term hypothyroidism was associated with significant decreases in adrenal weights, only long-term hypothyroid rats showed changes in adrenal function with a significant decrease of ACTH-induced corticosterone release from cultured adrenal cells. The data suggest that long-term hypothyroidism is associated with adrenal insufficiency with abnormalities in all three components of the HPA axis. Short-term hypothyroidism, on the other hand, is associated with increased pituitary corticotroph responsiveness to CRH.

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Hypersecretion of corticotrophin-releasing hormone and arginine vasopressin in hypothyroid male rats as estimated with push-pull perfusion

Cited by 20 publications

References 29 publications

Studies on the Functional Relationship between Thyroid, Adrenal and Gonadal Hormones

Studies on the Functional Relationship between Thyroid, Adrenal and Gonadal Hormones

Inhibition of Stress-Induced Adrenocorticotropin and Prolactin Secretion Mediating Hypophysiotropic Factors by Antagonist of AMPA Type Glutamate Receptor

Effects of short- and long-duration hypothyroidism on hypothalamic–pituitary–adrenal axis function in rats: In vitro and in situ studies

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