title: A comparative methodical study of the faecal steroid analysis on birds: looking for a valid method of testosterone determination.
abstract: In a comparative study, a relatively simple and high sensitivity method was developed for analysis of testosterone-equivalent(s) in the faeces of different bird species. To determine the recovery of extractions and purifications, tritium-labelled testosterone was added to the wet samples. Then the samples were treated with sodium dodecil sulphate (SDS), an emulsificator to "open-up" the complex, lipid-coated particles of faecal samples. This emulsification resulted in the decrease of the quantity of interfering substances after diethyl-ether extraction and the linearity of the measured testosterone equivalents from aliquots in the range of 2 and 10 mg of faeces. In the RIA, we applied a group specific polyclonal testosterone antibody which cross-reacted with reduced metabolites and at a certain level with sulphate conjugates as well. The use of Helix enzymes did not modified significantly the results of the analysis relating to a low level of conjugated androgens in the faecal extracts. The biological validity of the method was tested on domestic cockerels, where between the plasma and faecal testosterone values a four hours phase shift was observed, with a correlation of 0.6355. This method is suitable for "non invasive", behavioural-ethological studies.
authors.affiliation: Department of Reproductive Biology, Szt. István University, H-2103 Gödöllo, Hungary. kelemen@fx.ro
authors.forename: K
authors.initials: K
authors.lastname: Kelemen
authors.forename: P
authors.initials: P
authors.lastname: Péczely
authors.forename: Zs
authors.initials: Z
authors.lastname: Szoke
authors.forename: V
authors.initials: V
authors.lastname: Ladjánszky
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D001717:Birds / Q000502:physiology*; D003902:Detergents / Q000737:chemistry; D004986:Ether / Q000737:chemistry; D005243:Feces / Q000737:chemistry*; D041981:Gastrointestinal Tract / Q000033:anatomy & histology / Q000737:chemistry; D008297:Male; D011863:Radioimmunoassay; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013223:Statistics as Topic; D013256:Steroids / Q000032:analysis*; D013739:Testosterone / Q000032:analysis*
chemical_list: D003902:Detergents; D012997:Solvents; D013256:Steroids; D004986:Ether; D012967:Sodium Dodecyl Sulfate; D013739:Testosterone