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Home / Equine Research Bank / Drug Test Anal / Equine metabolism of the growth hormone secretagogue MK-0677...
Drug testing and analysis2022; 14(7); 1273-1290; doi: 10.1002/dta.3252

Equine metabolism of the growth hormone secretagogue MK-0677 in vitro and in urine and plasma following oral administration.

Abstract: Ibutamoren mesylate, or MK-0677, is an orally active, nonpeptide growth hormone secretagogue that has been developed to stimulate excretion of endogenous growth hormone. It has been evaluated for the treatment of a range of clinical conditions but is not available therapeutically. Nonetheless, MK-0677 is widely available to purchase online, sold as 'supplement' products. The mode of action and relative ease of purchase make MK-0677 a potential threat with regard to sports doping. The aim of this study was to investigate the metabolism of MK0677 in the horse following in vitro incubation and oral administration to two Thoroughbred racehorses, in order to identify the most appropriate analytical targets for doping control laboratories. Liquid chromatography high resolution mass spectrometry was used for metabolite identification, and subsequently, liquid chromatography-tandem mass spectrometry was used to generate full metabolite profiles for post-administration urine and plasma samples. Fourteen phase I metabolites were identified in vitro; 13 of these were subsequently detected in urine and nine in plasma collected post-administration, alongside the parent compound in both matrices. In both urine and plasma, the longest duration of detection was observed for an O-dealkylated metabolite of MK-0677, and therefore, this would be the best target for the detection of MK-0677 administration. MK-0677 and the O-dealkylated metabolite were found to be excreted largely unconjugated in urine and plasma.
© 2022 John Wiley & Sons, Ltd.
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Publication Date: 2022-03-25 PubMed ID: 35302297DOI: 10.1002/dta.3252Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates the metabolism of a growth hormone secretagogue called MK-0677 in horses, following both in vitro incubation and oral administration to two Thoroughbred racehorses, with the aim of identifying optimal analytical targets for doping control.

Objective of the Study

  • The study intends to explore the metabolism of a nonpeptide growth hormone, MK-0677, in horses by observing it under lab conditions (in vitro) and after being ingested by two Thoroughbred racehorses.
  • The aim is to identify the best analytical targets to detect the use of MK-0677 in doping, given its relatively easy availability and the potential threat it poses for sports doping.

Methods Used in the Study

  • To comprehend the metabolism of MK-0677, the study makes use of liquid chromatography high-resolution mass spectrometry. This technique helps in identifying metabolites of MK-0677.
  • Once the metabolites are identified, liquid chromatography-tandem mass spectrometry is used to generate detailed metabolite profiles for urine and plasma samples gathered post-administration.

Findings of the Study

  • In the lab, the researchers were able to identify fourteen phase I metabolites of MK-0677. Of these, thirteen were subsequently detected in urine and nine in blood after MK-0677 was ingested by the horses.
  • Alongside these metabolites, the parent compound, i.e., MK-0677, was also found in both post-administration urine and plasma samples.
  • An O-dealkylated metabolite of MK-0677 had the longest detection duration in both urine and plasma, making it the ideal target for doping detection.
  • Notably, MK-0677 and the O-dealkylated metabolite were discovered to be primarily unconjugated in the urine and plasma, meaning they were free and not combined with other substances.

Implications of the Study

  • The results of this study could be beneficial for doping control laboratories, providing them with a potential detection method for MK-0677 use.
  • Specifically, focusing on the O-dealkylated metabolite, which has the longest detection window, could improve doping detection strategies in sports involving horses, thereby maintaining the integrity of these competitions.

Cite This Article

APA
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Van Eenoo P. (2022). Equine metabolism of the growth hormone secretagogue MK-0677 in vitro and in urine and plasma following oral administration. Drug Test Anal, 14(7), 1273-1290. https://doi.org/10.1002/dta.3252

Publication

Drug testing and analysis
ISSN: 1942-7611
NlmUniqueID: 101483449
Country: England
Language: English
Volume: 14
Issue: 7
Pages: 1273-1290

Researcher Affiliations

Cutler, Charlotte
  • LGC Ltd, Fordham, UK.
  • Doping Control Laboratory, Ghent University (Ugent), Ghent, Belgium.
Viljanto, Marjaana
  • LGC Ltd, Fordham, UK.
Taylor, Polly
  • LGC Ltd, Fordham, UK.
Habershon-Butcher, Jocelyn
  • British Horseracing Authority, London, UK.
Van Eenoo, Peter
  • Doping Control Laboratory, Ghent University (Ugent), Ghent, Belgium.

MeSH Terms

  • Administration, Oral
  • Animals
  • Chromatography, Liquid / methods
  • Doping in Sports
  • Growth Hormone
  • Horses
  • Indoles
  • Secretagogues
  • Spiro Compounds
  • Substance Abuse Detection / methods

References

This article includes 42 references
  1. Smith RG, Cheng K, Schoen WR. A nonpeptidyl growth hormone secretagogue.. Science 1993;260(5114):1640-1643.
  2. Chapman IM, Pescovitz OH, Murphy G. Oral administration of growth hormone (GH) releasing peptide-mimetic MK-677 stimulates the GH/insulin-like growth factor-I axis in selected GH-deficient adults.. J Clin Endocrinol Metabol 1997;82(10):3455-3463.
  3. Reed ML, Merriam GR, Kargi AY. Adult growth hormone deficiency - benefits, side-effects, and risks or growth hormone replacement.. Front Endocrinol 2013;4(64):1-14.
  4. Pratchett AA, Nargund RP, Tata JR. Design and biological activities of L-163,191 (MK-0677): A potent, orally active growth hormone secretagogue.. Proc Natl Acad Sci U S a 1995;92(15):7001-7005.
  5. Codner E, Cassorla F, Tiulpakov AN. Effects of oral administration of ibutamoren mesylate, a nonpeptide growth hormone secretagogue, on the growth hormone - insulin-like growth factor I axis in growth hormone-deficient children.. Clin Pharmacol Ther 2001;70(1):91-98.
  6. Murphy MG, Plunkett LM, Gertz GJ. MK-0677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.. J Clin Endocrinol Metabol 1998;83(2):320-325.
  7. Bach MA, Rockwood K, Zetterberg C. The effects of MK-0677, an oral growth hormone secretagogue, in patients with hip fracture.. J am Geriatr Soc 2004;52(4):516-523.
  8. Adunsky A, Chandler J, Heyden N. MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: A multicentre, randomized, placebo-controlled phase IIb study.. Arch Gerontol Geriatr 2011;53(2):183-189.
  9. Hersch EC, Merriam GR. Growth hormone (GH)-releasing hormone and GH secretagogues in normal aging: Fountain of youth or pool of tantalus?. Clin Interv Aging 2008;3(1):121-129.
  10. Chapman IM, Bach MA, Van Cauter E. Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects.. J Clin Endocrinol Metabol 1996;81(12):4249-4257.
  11. Campbell GA, Patrie JT, Gaylinn BD, Thorner MO, Bolton WK. Oral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor I in hemodialysis patients: a randomized blind study.. Nephrol Dial Transplant 2018;33(3):523-530.
  12. Murphy MG, Bach MA, Plotkin D. Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults.. J Bone Miner Res 1999;14(7):1182-1188.
  13. Van Wagoner RM, Eichner A, Bhasin S, Deuster PA, Eichner D. Chemical composition and labelling of substances marketed as selective androgen receptor modulators and sold via the internet.. Jama 2017;318(20):2004-2010.
  14. Leaney AE, Beck P, Biddle S. Analysis of supplements available to UK consumers purporting to contain selective androgen receptor modulators.. Drug Test Anal 2021;13(1):122-127.
  15. International Federation of Horseracing Authorities. International agreement on breeding, racing and wagering.. 2020.
  16. World Anti-Doping Agency. The 2008 prohibited list international standard.. 2007.
  17. Sobolevsky T, Prasolov I, Rodchenkov G. Urinary metabolism of ibutamoren, a small molecule growth hormone secretagogue.. In: 31st Cologne Workshop on Dope Analysis. Cologne, Germany: Manfred-Donike Institute; 2013.
  18. Sobolevsky T, Krotov G, Dikunets M, Nikitina M, Mocalova E, Rodchenkov G. Anti-doping analyses at the Sochi Olympic and Paralympic Games 2014.. Drug Test Anal 2014;6(11-12):1087-1101.
  19. Min H, Han B, Sung C. LC-MS/MS method for the simultaneous analysis of growth hormone-releasing peptides and secretagogues in human urine.. Mass Spectrom Lett 2016;7(3):55-63.
  20. Dmitrieva EV, Temerdashev AZ, Azaryan AA, Gashimova EM. Determination of Andarine (S-4), a selective androgen receptor modulator, and ibutamoren (MK-677), a nonpeptide growth hormone secretagogue, in urine by ultra-high performance liquid chromatography with tandem mass-spectrometric detection.. Journal of Analytical Chemistry 2018;73(7):674-678.
  21. Philip M, Karakka Kal AK, Subhahar MB, Perwad Z, Karatt TK. Characterization of equine liver microsome-generated metabolites of growth hormone secretagogue small molecule ibutamoren.. Rapid Comm Mass Spec 2021;35(23):e9201.
    doi: 10.1002/rcm.9201google scholar: lookup
  22. Gao W, Wu Z, Bohl CE, Yang J, Miller DD, Dalton JT. Characterization of the in vitro metabolism of selective androgen receptor modulator using human, rat, and dog liver enzyme preparations.. Drug Metab Dispos 2006;34(2):243-253.
  23. Thevis M, Thomas A, Fußhöller G, Beuck S, Geyer H, Schänzer W. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator andarine (S-4) for routine doping control purposes.. Rapid Comm. Mass Spec. 2010;24:2245-2254.
  24. Thevis M, Gerace E, Thomas A. Characterization of in vitro generated metabolites of the selective androgen receptor modulators S-22 and S-23 and in vivo comparison to post-administration canine urine specimens.. Drug Test Anal 2010;2(11-12):589-598.
  25. Hansson A, Knych H, Stanley S, Thevis M, Bondesson U, Hedeland M. Characterisation of equine urinary metabolites of selective androgen receptor modulators (SARMs) S1, S4 and S22 for doping control purposes.. Drug Test Anal 2015;7(8):673-683.
  26. Cox HD, Eichner D. Detection of LGD-4033 and its metabolites in athlete urine samples.. Drug Test Anal 2016;9(1):127-134.
  27. Fragakaki AG, Sakellariou P, Kiousi P. Human in vivo metabolism study of LGD-4033.. Drug Test Anal 2018;10(11-12):1635-1645.
  28. Cutler C, Viljanto M, Hincks P, Habershon-Butcher J, Muir T, Biddle S. Investigation of the metabolism of the selective androgen receptor modulator LGD-4033 in equine urine, plasma and hair following oral administration.. Drug Test Anal 2020;12(2):247-260.
  29. Hansson A, Knych H, Stanley S. Equine in vivo-derived metabolites of SARM LGD-4033 and comparison with human and fungal metabolites.. J Chromatogr B 2018;1074-1075.
  30. Scarth JP, Clarke AD, Teale P, Pearce C. Comparitive in vitro metabolism of the ‘designer’ streroid estra-4,9-diene-3,17-dione between the equine, canine and human: Identification of target metabolites for use in sports doping control.. Steroids 2010;75(10):643-652.
  31. Cutler C, Viljanto M, Taylor P. Equine metabolism of the selective androgen recptor modulator AC-262536 in vitro and in urine, plasma and hair following oral administration.. Drug Test Anal 2021;13(2):p369-p385.
  32. Dumasia MC. Identification of some N-hydroxylated metabolites of (±)-3,4-methylenedioxymethamphetamine in horse urine by gas chromatography-mass spectrometry.. Xenobiotica 2003;33(10):1013-1025.
  33. Beckett AH, Al-Sarraj S. N-oxidation of primary and secondary amines to give hydroxylamines - a general metabolic route.. J Pharm Pharmac 1972;24(11):916-917.
  34. Ramanathan R, Chowchury SK, Alton KB. Oxidative metabolites of drugs and xenobiotics: LC-MS methods to identify and characterize in biological matrices.. In: Identification and Quantification of Drugs, Metabolites and Metabolizing Enzymes by LC-MS; 2005.
  35. Becket AH, Bélanger PM. Metabolic N-oxidation of secondary and primary aromatic amines as a route to ring hydroxylation, to various N-oxygenated products, and to dealkylation of secondary amines.. Biochem Pharmacol 1975;25(2):211-214.
  36. Becket AH, Bélanger PM. The mechanism of metabolic N-oxidation of phentermine and chlorphentermine to their hydroxylamino- and nitroso-compounds.. J. Pharm. Pharmac. 1974;2(7):558-560.
  37. Feasel MG, Wohlfarth A, Nilles JM, Pang S, Kristovich RL, Huestis MA. Metabolism of carfentanil, an ultra-potent opioid, in human liver microsomes and human hepatocytes by high-resolution mass spectrometry.. AAPS J 2016;18(6):1489-1499.
  38. Cutler C, Hudson S. In vitro metabolism of the novel synthetic opioid agonist cyclopropylfentanyl and subsequent confirmation in authentic human samples using liquid chromatography-high resolution mass spectrometry.. Drug Test Anal 2019;11(8):1134-1143.
  39. Cashman JR, Park SB, Yang ZC, Wrighton SA, Jacob P, Benowitz NL. Metabolism of nicotine by human liver microsomes: stereoselective formation of trans-nicotine N'-oxide.. Chem re Toxicol 1992;5(5):639-646.
  40. Pirmohamed M, Williams D, Madden S, Templeton E, Park BK. Metabolism and bioactivation of clozapine by human liver in vitro.. J Pharmcol Exp Ther 1995;272(3):984-990.
  41. Kikura-Hanajiri R, Kawamura M, Miyajima A, Sunouchi M, Goda Y. Determination of a new designer drug, N-hydroxy-3,4-methylenedioxymethamphetamine and its metabolites in rats using ultra-performance liquid chromatography-tandem mass spectrometry.. For Sci Int 2010;198(1-3):62-69.
  42. The Association of Official Racing Chemists. AORC guidelines for the minimum criteria for identification by chromatography and mass spectrometry.. 2016.

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