Evaluation of three immunoassay systems for the assessment of urinary biomarkers of ovarian function in the endangered chinchilla (Chinchilla lanigera).

PONZIO MF; MASTROMONACO G; GALEANO MG; GILMAN C; RUIZ RD; FIOL DE CUNEO M

Viena

Congreso; International Society of Wildlife Endocrinologists Annual Meeting; 2012

International Society of Wildlife Endocrinologists

Evaluation of three immunoassay systemsfor the assessment of urinary biomarkers ofovarian function in the endangered chinchilla(Chinchilla lanigera)Ponzio M. F.1, Mastromonaco G.F.2, Galeano M.G.1, Gilman C.2, Ruiz R. D.1, Fiol de Cuneo M.11Instituto de Fisiología, Facultad de Ciencias Médicas,Universidad Nacional de Córdoba, Córdoba, Argentina2Reproductive Physiology, Toronto Zoo, Toronto, Canada,e-mail: ponziomarina@hotmail.comIntensive hunting for fur placed chinchillapopulations at the brink of extinction (IUCNcritically endangered - Appendix I of CITES).Although native chinchilla are extremely rare, ahybrid has been bred for fur production, providinga unique model to develop procedures that couldbe applied to their endangered counterparts.Despite its biological and economic importance,little scientifi c information is available about thisspecies’ basic reproductive physiology, a keyaspect for the implementation of captive breedingprogrammes. Attempts to obtain repeated bloodsamples from chinchillas were unsuccessful becauseof their stress-susceptible nature. Therefore, noninvasivetechniques provided a unique opportunity,allowing long-term endocrine monitoring whileavoiding the stress-evoking stimuli of restraint andvenipuncture. The objective of the present study wasto test the validity and accuracy of different assayssystems for quantifi cation of urinary biomarkers ofovarian activity in the chinchilla. Urinary steroidmetabolites were assessed in 24 h urine longitudinalsamples before and after the injection of eCG(Novormon, Syntex, 30 I.U., n=6). Hormoneassays tested included creatinine (colorimetricassay from creatinine standard set, Sigma #C3613),pregnanediol glucuronide (PdG, C. MunroR13904) and oestrogens (EC, C. Munro R522-2)by EIA. Comparative profi les of progesterone (P)and oestradiol (E) metabolites using RIA were alsodetermined (I125 RIA kits, Coat-A-Count, Siemens).Finally, same samples were quantifi ed for 17β-oestradiol and progesterone metabolites using anelectrochemiluminescence immunoassay (RocheDiagnostics). After eCG injection, elevation of46Wiener Tierärztliche Monatsschrift – Veterinary Medicine Austria 99 (2012(Suppl. 1) )urinary PdG and EC metabolites above baselinelevels occurred after 7 and 9 days respectively,reaching values of 2720±1110 and 22.5±9.7 ng/mg creatinine. Signifi cantly lower metaboliteconcentrations were detected using RIA for Eand P determinations, yet the profi les obtainedwere similar to those using EIA for EC and PdG.An improved understanding of these aspects willundoubtedly help researchers to use more effectiveassay systems for the evaluation of reproductivefunction in this species.