Effects of Immunoneutralization of Endogenous Opioid Peptides on the Hypothalamic-Pituitary-Thyroid Axis in Rats

Mitsuma, Terunori; Hirooka, Y; Nogimori, T

doi:10.1159/000182700

Cited by 10 publications

(5 citation statements)

References 9 publications

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“…Administration of dynorphin or (3-neoendorphin de creases TRH hypothalamic content and plasma TSH lev els [36,37]; conversely, administration of endogenous opioid peptide antisera increases plasma TSH concentra tions [38], Because the opioid peptide system is activated during stress [reviewed in ref. 14], the stress-induced inhi bition of HPT axis function observed in young rats might 511 also be mediated by opioid peptides.…”

Section: Discussionmentioning

confidence: 99%

Stress-Induced Inhibition of the Hypothalamic-Pituitary-Thyroid Axis Is Attenuated in the Aged Fischer 344/N Male Rat

et al. 1995

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Aging is associated with a progressive decrement in the basal activity of the hypothalamic-pituitary-thyroid axis in male Fischer 344/N rats. The aim of this study was to determine whether stress influences the activity of this axis in young and old rats. As prolactin and growth hormone share some regulatory mechanisms with thyrotropin-releasing and thyroid-stimulating hormones, which are influenced by stress, the plasma levels of these two hormones were also determined during immobilization (Immo). To accomplish this, young (3-month-old) and old (23-month-old) male 344/N Fischer rats were immobilized for 2 h; blood was collected by cannulation from the tail artery at different intervals during Immo (0, 5, 30, 60, and 120 min), and brains were removed at the end of Immo. The basal plasma levels of thyroid-stimulating hormone were similar in both groups, but were significantly and progressively inhibited by Immo in young, but not in old rats. The baseline plasma levels of total triiodothyronine were slightly lower in old than in young rats; Immo caused a significant decrease of total triiodothyronine levels only in the young animals. The baseline plasma levels of free triiodothyronine were similar and were not altered by Immo in either age group. The paraventricular nucleus thyrotropin-releasing hormone mRNA levels were lower in old than in young rats under basal conditions; under stress they were significantly inhibited in young, but remained unchanged in old rats. The basal thyroid-stimulating hormone beta mRNA levels in the anterior pituitary were significantly lower in old than in young rats, but were not affected by Immo in either age group. The plasma prolactin levels were similar at baseline and were significantly increased by Immo in both age groups, but significantly more in old than in young rats. The plasma growth hormone levels were also similar at baseline; they were significantly decreased by Immo to a similar extent in both age groups. In summary, these data indicate that the stress-induced decrease in plasma thyroid-stimulating hormone is in part mediated at the level of the hypothalamic thyrotropin-releasing hormone neuron and that this phenomenon is attenuated in the aged rat.

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Section: Discussionmentioning

confidence: 99%

Stress-Induced Inhibition of the Hypothalamic-Pituitary-Thyroid Axis Is Attenuated in the Aged Fischer 344/N Male Rat

et al. 1995

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“…Also dopamine, often infused for inotropic and vasoactive support in the PICU, suppressed TSH secretion in pediatric critically ill patients [50]. Rat studies suggested that opioids affect the TRH-stimulated TSH release [51] but studies in humans revealed conflicting results [52][53][54]. Less commonly used drugs in PICU, such as antiepileptic medications including carbamazepine, oxcarbemazepine and valproic acid, may also alter pituitary responsiveness to TRH [49,55,56].…”

Section: Key Pointsmentioning

confidence: 99%

Nonthyroidal illness in critically ill children

Jacobs

Vanhorebeek

Berghe

2019

Current Opinion in Endocrinology, Diabetes &Amp; Obesity

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This review summarizes recent literature on non-thyroidal illness syndrome (NTI) and outcome of pediatric critical illness, to provide insight in pathophysiology and therapeutic implications.Recent findings: NTI is typically characterized by lowered triiodothyronine levels without compensatory TSH rise. Although NTI severity is associated with poor outcome of pediatric critical illness, it remains unclear whether this association reflects an adaptive protective response or contributes to poor outcome. Recently, two metabolic interventions that improved outcome also altered NTI in critically ill children. These studies shed new light on the topic, as the results suggested that the peripheral NTI component, with inactivation of thyroid hormone, may represent a beneficial adaptation, whereas the central component, with suppressed TSH-driven thyroid hormone secretion, may be maladaptive. There is currently insufficient evidence for treatment of NTI in children. However, the recent findings raised the hypothesis that reactivation of the central NTI component could offer benefit, which should be tested in RCTs. Summary: NTI in critically ill children can be modified by metabolic interventions. The peripheral, but not the central, component of NTI may be a beneficial adaptive response. These findings open perspectives for the development of novel strategies to improve outcome of critical illness in children.

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“…Os resultados com β-endorfina são absolutamente conflitantes, sendo relatados tanto aumento (83) quanto diminuição (84). No entanto, a imunoneutralização da β-endorfina endógena e da met-encefalina está associada ao aumento do TRH e à liberação de TSH em ratos, sugerindo um papel tônico inibitório destes opiáceos (85). Porém, em indivíduos com doença de Addison, normo ou hipocortisólicos, a naloxana, que é um antagonista opiáceo, inibe a secreção de TSH (82).…”

Section: Infecções E Estresseunclassified

Regulação da síntese e secreção de tireotrofina

Moura

2004

Arq Bras Endocrinol Metab

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The set point of thyrotropin (TSH) secretion is determined by the balance of a positive regulation of thyrotropin releasing hormone (TRH) and the strong negative regulation exerted by thyroid hormones. In addition, there are other regulators superimposed on this main axis such as somatostatin and dopamine, which act as inhibitors of TSH secretion, and central alpha-adrenergic pathways that are predominantly stimulatory and involved in the cold-induced thyroid activation. Nutritional status and leptin also regulate TSH by stimulating TRH neurons through direct and indirect mechanisms. Stress is also involved in lowering TRH/TSH secretion possibly through glucocorticoids, cytokines and opioids. Recently, a new regulatory pathway has been proposed, via peptides produced in pituitary, acting in an autocrine/paracrine manner. Among those, more consistent data are available on neuromedin B, gastrin-releasing peptide and pituitary leptin, which act as local inhibitors of TSH release. Neonatal programming of TSH secretion set point is also discussed.

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Effects of Immunoneutralization of Endogenous Opioid Peptides on the Hypothalamic-Pituitary-Thyroid Axis in Rats

Cited by 10 publications

References 9 publications

Stress-Induced Inhibition of the Hypothalamic-Pituitary-Thyroid Axis Is Attenuated in the Aged Fischer 344/N Male Rat

Stress-Induced Inhibition of the Hypothalamic-Pituitary-Thyroid Axis Is Attenuated in the Aged Fischer 344/N Male Rat

Nonthyroidal illness in critically ill children

Regulação da síntese e secreção de tireotrofina

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