Thyrotropin TRH (25mg)

Thyrotropin Peptide

Thyroid hormones are considered to be growth and metabolism regulators. In order to maintain the synchrony of these regulating mechanisms and hemostasis, hormones released by the hypothalamus are called Thyrotropin-releasing hormone (TRH).⁽¹⁾ Scientists consider the main function of Thyrotropin-releasing hormone (TRH) to be the maintenance of the levels of thyroid hormones.⁽²⁾ While TRH is an endogenous compound, a synthetic peptide was developed with the hopes of simulating TRH characteristics and is known as Thyrotropin, or Protirelin.⁽³⁾

Overview

Thyrotropin is the synthetic analogue of the endogenous peptide hormone Thyrotropin-releasing hormone.⁽³⁾ Structurally analogous to TRH, Thyrotropin is a tripeptide composed of three amino acid residues connected in a sequential form.⁽³⁾  Researchers consider Thyrotropin to potentially function via binding to the thyrotropin-releasing hormone (TRH) receptors TRH-1 and TRH-2.⁽⁶⁾

On binding with these receptors, which are mediated by G proteins, a possible cascade of signals may be generated. First, a hydrolase enzyme may be activated, which in turn may cause a breakdown of an existing compound, producing inositol. Research indicates that Inositol may bind with another receptor, a calcium channel, thereby resulting in possible increased cellular levels of calcium which may activate protein kinase C, potentially leading to elevated phosphorylation of secondary messenger enzymes.

All these signals carry the collective potential to modify gene expression in the nucleus of a cell, which may transduce the TRH binding signal to stimulate the thyroid gland to increase or decrease thyroid hormone production.

Research and Clinical Studies

Thyrotropin Peptide and Amyotrophic Lateral Sclerosis

Researchers are considering the potential function of Thyrotropin in Amyotrophic Lateral Sclerosis (ALS). Researchers suggest that Thyrotropin may act as a neuromodulator during the hyperactivity of the hypothalamic nervous system, which may assert some mitigation of Amyotrophic Lateral Sclerosis (ALS) symptoms.⁽⁸⁾

Thyrotropin Peptide and Behavioral Research

Initial clinical studies conducted to assess the potential of the peptide were somewhat hindered as researchers considered the peptide might not be able to cross the blood brain barrier.⁽⁹⁾ Scientists consider the blood brain barrier to be one of the most difficult membranes to cross as it is composed of closely spaced cells in order to prevent toxic substances from crossing over and reaching the brain.⁽¹⁰⁾

In this study,⁽⁹⁾ the peptide was presented into the spinal theca (or cerebrospinal fluid). Eight test subjects with depressive symptoms were enrolled in a double-blind clinical trial study. Upon analysis, it was observed by the researchers that five out of the eight subjects exhibited an apparent 50% or more reduction in depressive behavior.

In another study,⁽¹¹⁾ 44 subjects were presented with the "Thyrotropin test".  Out of the 44 test subjects, 19 exhibited an apparently blunted response to the test, indicating possible hypothyroidism, whereas 6 exhibited an apparently higher response to the test. Five of these subjects with a high augmented response were reported to naturally produce antithyroid antibodies. Through this study, researchers posited that the peptide may serve to indicate improper functioning of the thyroid gland, or determine any possible behavioral depressors.

Thyrotropin Peptide and Blood Pressure

In one clinical study which sought to conduct diagnostic tests on test subjects, it was suggested by the researchers that the peptide might contribute to an elevation in blood pressure rate. In this study,⁽¹²⁾ eight subjects were examined one day before, the day after, and four weeks after heart surgery. All these subjects were given Thyrotropin. While the peptide did not appear to induce any significant changes in the levels of heart rate and thyroid hormones, the blood pressure rates reportedly increased on all three days. These results indicate that Thyrotropin may lead to increased blood pressure rates, and hence it is important for the clinical researcher to be aware of the subjects' pre-existing heart conditions when it comes to peptide administration.

Thyrotropin peptide is available for research and laboratory purposes only. Please review and adhere to our Terms and Conditions before ordering.

References:

1. Shahid MA, Ashraf MA, Sharma S. Physiology, Thyroid Hormone. [Updated 2021 May 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021. https://www.ncbi.nlm.nih.gov/books/NBK500006/
2. Michigan Medicine, University of Michigan Health. March 31, 2020. https://www.uofmhealth.org/health-library/ug1836
3. National Center for Biotechnology Information. "PubChem Compound Summary for CID 638678, Protirelin" PubChem, https://pubchem.ncbi.nlm.nih.gov/compound/Protirelin.
4. Boler J, Enzmann F, Folkers K, Bowers CY, Schally AV. The identity of chemical and hormonal properties of the thyrotropin releasing hormone and pyroglutamyl-histidyl-proline amide. Biochem Biophys Res Commun. 1969 Nov 6;37(4):705-10. https://pubmed.ncbi.nlm.nih.gov/4982117/
5. Kobayashi, Naotake et al. “Discovery of the Orally Effective Thyrotropin-Releasing Hormone Mimetic: 1-{N-[(4S,5S)-(5-Methyl-2-oxooxazolidine-4-yl)carbonyl]-3-(thiazol-4-yl)-l-alanyl}-(2R)-2-methylpyrrolidine Trihydrate (Rovatirelin Hydrate).” ACS omega vol. 3,10 (2018): 13647-13666. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6217654/
6. A. Eugene Pekary, Protirelin should be used with care in patients with ischemic heart disease, obstructive airway disease, or severe hypopituitarism (Parfitt, 1999). https://www.sciencedirect.com/topics/medicine-and-dentistry/protirelin
7. Amyotrophic Lateral Sclerosis (ALS) Fact Sheet. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Amyotrophic-Lateral-Sclerosis-ALS-Fact-Sheet
8. Miller SC, Warnick JE. Protirelin (thyrotropin-releasing hormone) in amyotrophic lateral sclerosis. The role of androgens. Arch Neurol. 1989 Mar;46(3):330-5. https://pubmed.ncbi.nlm.nih.gov/2563937/
9. Marangell LB, George MS, Callahan AM, Ketter TA, Pazzaglia PJ, L'Herrou TA, Leverich GS, Post RM. Effects of intrathecal thyrotropin-releasing hormone (protirelin) in refractory depressed patients. Arch Gen Psychiatry. 1997 Mar;54(3):214-22. https://pubmed.ncbi.nlm.nih.gov/9075462/
10. Blood-brain barrier. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/blood-brain-barrier
11. Sternbach HA, Gold MS, Pottash AC, Extein I. Thyroid failure and protirelin(thyrotropin-releasing hormone) test abnormalities in depressed outpatients. JAMA. 1983 Mar 25. https://pubmed.ncbi.nlm.nih.gov/6402617/
12. Zaloga GP, Chernow B, Zajtchuk R, Chin R, Rainey TG, Lake CR. Diagnostic dosages of protirelin (TRH) elevate BP by noncatecholamine mechanisms. Arch Intern. https://pubmed.ncbi.nlm.nih.gov/6428340/
13. Borowski GD, Garofano CD, Rose LI, Levy RA. Blood pressure response to thyrotropin-releasing hormone in euthyroid subjects. J Clin Endocrinol Metab. 1984 Jan;58(1):197-200. https://pubmed.ncbi.nlm.nih.gov/6417153/
14. Duntas L, Keck FS, Loos U, Pfeiffer EF. Pharmakokinetik und Pharmakodynamik von Protirelin (TRH) beim Menschen [Pharmacokinetics and pharmacodynamics of protirelin (TRH) in man]. Dtsch Med Wochenschr. 1988 Sep 2;113(35):1354-7. German. https://pubmed.ncbi.nlm.nih.gov/3137012/