Prolonged Inhibition of Presynaptic Catecholamine Synthesis With α-Methyl-Para-Tyrosine Attenuates the Circadian Rhythm of Human TSH Secretion

Zimmermann, Ralf; Krahn, Lois E.; Klee, George G.; Ditkoff, Edward C.; Ory, Steven J.; Sauer, Mark V.

doi:10.1177/107155760100800309

Cited by 4 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, previous clinical studies ( Engelman et al 1968 a , b , Nasrallah et al 1977 , Nicoletti et al 1986 , Perry et al 1990 , Sand et al 1997 , Steinsapir et al 1997 , Zimmermann et al 2001 , Wachtel et al 2015 , Butz et al 2017 , Hamidi et al 2017 , Naruse et al 2018 , Takekoshi et al 2019 ) did not assess the effects of αMPT on glucose metabolism (Supplementary Table 1, see section on supplementary materials given at the end of this article). Additionally, whether αMPT administration enables safe surgical treatment remains unclear, even though αMPT is indicated to effectively reduce MN and normetanephrine (NMN) levels.…”

Section: Introductionmentioning

confidence: 96%

Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Matsuo,

Ashida,

Nagayama

et al. 2023

Endocrine Oncology

View full text Add to dashboard Cite

Objective Metyrosine (alpha-methyl-para-tyrosine) effectively reduces catecholamine levels in patients with pheochromocytoma/paraganglioma. However, improvements in physiological and metabolic parameters and changes in endocrine function associated with metyrosine administration should be validated in comparison to surgery. This study was performed to confirm the effects of metyrosine on the physiological, metabolic, and endocrinological functions of patients with pheochromocytoma/paraganglioma in the perioperative period. Design This retrospective cohort study was performed at a single university hospital. Methods We included ten patients with pheochromocytoma/paraganglioma who received oral metyrosine after α-blocker therapy and consecutive surgeries. Urinary catecholamine metabolite levels and other clinical parameters were evaluated before and after metyrosine administration, and 1 week after surgery. Results The mean age was 53.1 ± 16.1 years. Of the ten participants (four men and six women), nine had pheochromocytoma and one had paraganglioma. The median maximum metyrosine dose was 750 mg/day. Urinary catecholamine metabolite levels significantly decreased in a dose-dependent manner after metyrosine administration. Both systolic and diastolic blood pressure significantly decreased after metyrosine and surgical treatment. Metyrosine administration significantly improved insulin sensitivity, although surgery improved the the basal insulin secretion. Additionally, serum prolactin and thyroid-stimulatory hormone levels were significantly increased by metyrosine treatment, whereas plasma renin activity was decreased. Conclusions Metyrosine significantly reduced catecholamines in patients with pheochromocytoma/paraganglioma and ensured the safety of the surgery. Adjustment of metyrosine administration may make surgical pretreatment more effective in achieving stabilized blood pressure and improving glucose metabolism. Endocrine parameters may manifest as the systemic effects of metyrosine administration.

show abstract

Section: Introductionmentioning

confidence: 96%

Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Matsuo,

Ashida,

Nagayama

et al. 2023

Endocrine Oncology

View full text Add to dashboard Cite

show abstract

“…Previous studies have demonstrated that administration of AMT increases endogenous prolactin levels both in animals and humans [6][7][8][9]. Thus, measuring AMT concentrations in plasma could help establish AMT pharmacokinetics and also aid in potentially developing a pharmacoki- netic/pharmacodynamic (PK/PD) model between AMT and prolactin.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a liquid chromatography–tandem mass spectrometric method for the determination of α-methyltyrosine in human plasma

Humphries

Ruterbories

Chan

et al. 2004

Journal of Chromatography B

View full text Add to dashboard Cite

Untitled

Zisapel

2001

Cellular and Molecular Neurobiology

169

View full text Add to dashboard Cite

To review the interaction between melatonin and the dopaminergic system in the hypothalamus and striatum and its potential clinical use in dopamine-related disorders in the central nervous system. Medline-based search on melatonin-dopamine interactions in mammals. Melatonin. the hormone produced by the pineal gland at night. influences circadian and seasonal rhythms, most notably the sleep-wake cycle and seasonal reproduction. The neurochemical basis of these activities is not understood yet. Inhibition of dopamine release by melatonin has been demonstrated in specific areas of the mammalian central nervous system (hypothalamus, hippocampus, medulla-pons, and retina). Antidopaminergic activities of melatonin have been demonstrated in the striatum. Dopaminergic transmission has a pivotal role in circadian entrainment of the fetus, in coordination of body movement and reproduction. Recent findings indicate that melatonin may modulate dopaminergic pathways involved in movement disorders in humans. In Parkinson patients melatonin may, on the one hand, exacerbate symptoms (because of its putative interference with dopamine release) and, on the other, protect against neurodegeneration (by virtue of its antioxidant properties and its effects on mitochondrial activity). Melatonin appears to be effective in the treatment of tardive dyskinesia. a severe movement disorder associated with long-term blockade of the postsynaptic dopamine D2 receptor by antipsychotic drugs in schizophrenic patients. The interaction of melatonin with the dopaminergic system may play a significant role in the nonphotic and photic entrainment of the biological clock as well as in the fine-tuning of motor coordination in the striatum. These interactions and the antioxidant nature of melatonin may be beneficial in the treatment of dopamine-related disorders.

show abstract

Prolonged Inhibition of Presynaptic Catecholamine Synthesis With α-Methyl-Para-Tyrosine Attenuates the Circadian Rhythm of Human TSH Secretion

Abstract: Through its inhibitory effect on TRH, norepinephrine appeared to be involved in the regulation of TSH.

Cited by 4 publications

References 23 publications

Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Development and validation of a liquid chromatography–tandem mass spectrometric method for the determination of α-methyltyrosine in human plasma

Untitled

Contact Info

Product

Resources

About