title: Clarification of emu serum for peptide hormone assay using polyethylene glycol precipitation.
abstract: Interference in radioimmunoassays (RIAs) was frequently encountered during endocrinological studies of the emu (Dromaius novaehollandiae). Interference was greatest when serum was cloudy or opaque. Such samples appeared seasonally, in spring and summer during the phase of fat deposition, and in the winter when females were laying. These poor quality samples did not allow accurate measurement by RIAs of several peptide hormones for a full year. To prepare them for assay, these sera were clarified using a polyethylene glycol (PEG) solution at a final concentration of 7.5%. This treatment was effective in most cases. After treatment with the PEG, recoveries of LH, glucagon, and prolactin were greater than 75% and that for insulin was 40%. Regardless of the level of recovery, there was a high correlation of assay results between non-opaque native and PEG-treated sera. Serum samples containing large amounts of interfering high molecular weight components, such as lipoproteins, can be clarified with PEG, enabling their accurate measurement by RIA.
authors.affiliation: School of Animal Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley 6009, WA, Australia. jkvc@uiuc.edi
authors.forename: J K
authors.initials: JK
authors.lastname: Van Cleeff
authors.forename: M A
authors.initials: MA
authors.lastname: Blackberry
authors.forename: D
authors.initials: D
authors.lastname: Blache
authors.forename: G B
authors.initials: GB
authors.lastname: Martin
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility / Q000502:physiology; D005934:Glucagon / Q000097:blood; D007328:Insulin / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009919:Orchiectomy; D010063:Ovum / Q000378:metabolism; D046108:Palaeognathae / Q000097:blood*; D036361:Peptide Hormones / Q000097:blood*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011388:Prolactin / Q000097:blood; D011786:Quality Control; D011863:Radioimmunoassay
chemical_list: D007328:Insulin; D036361:Peptide Hormones; D011092:Polyethylene Glycols; D011388:Prolactin; D007986:Luteinizing Hormone; D005934:Glucagon