title: Prandial ghrelin attenuation provides evidence that des-acyl ghrelin may be an artifact of sample handling in human plasma.
abstract: BACKGROUND
  Plasma acyl and des-acyl ghrelin are thought of as components of total ghrelin, but this has never been validated using ex vivo spiking experiments, human sample collection comparisons and fit-for-purpose translatable assays.
  
  
  RESULTS
  Acyl ghrelin plasma stability was analyzed by LC-MS/MS and it revealed that acyl ghrelin is enzymatically and chemically converted to des-acyl ghrelin in the presence of active serine proteases and HCl. ELISAs with less than 30% total error were used to assess acyl ghrelin behavior in matched authentic human samples. Acyl and total ghrelin were not statistically different in 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride samples and acyl ghrelin losses in K(2)EDTA plasma were accounted for in des-acyl ghrelin formation.
  
  
  CONCLUSIONS
  Acyl ghrelin is total ghrelin and des-acyl ghrelin should not be detectible in healthy human plasma under optimal sample handling and assaying conditions.
authors.affiliation: Department of Pharmacokinetics, Dynamics & Metabolism, Pfizer Global R&D, Groton Laboratories, Groton, CT 06340, USA. matthew.blatnik@pfizer.com
authors.forename: Matthew
authors.initials: M
authors.lastname: Blatnik
authors.forename: Catherine I
authors.initials: CI
authors.lastname: Soderstrom
authors.forename: Mark
authors.initials: M
authors.lastname: Dysinger
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Fraser
mesh_terms: D000328:Adult; D016477:Artifacts; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D054439:Ghrelin / Q000097:blood* / Q000138:chemical synthesis / Q000302:isolation & purification; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D011480:Protease Inhibitors / Q000737:chemistry; D057057:Serine Proteases / Q000737:chemistry / Q000378:metabolism; D052616:Solid Phase Extraction; D013450:Sulfones / Q000737:chemistry; D053719:Tandem Mass Spectrometry
chemical_list: D054439:Ghrelin; D011480:Protease Inhibitors; D013450:Sulfones; C422650:ghrelin, des-n-octanoyl; C002010:4-(2-aminoethyl)benzenesulfonylfluoride; D057057:Serine Proteases; D006851:Hydrochloric Acid