Radioimmunoassay for etorphine in horses with a /sup 125/I analog of etorphine

Journal Article · Sun May 01 04:00:00 EDT 1988 · Am. J. Vet. Res.; (United States)

OSTI ID:7002439

Tai, C L; Wang, C; Weckman, T J; Popot, M A; Woods, W E; Yang, J M; Blake, J; Tai, H H; Tobin, T

To improve the sensitivity and specificity of screening for etorphine in horses, an /sup 125/I-labeled etorphine analog was synthesized and an antibody to etorphine was raised in rabbits. A radioimmunoassay (RIA) for etorphine was developed, using these reagents. Bound and free /sup 125/I-labeled etorphine was separated by a double-antibody method that reduced interference from materials associated with equine urine. The /sup 125/I-labeled etorphine binding was rarely greater than 250 pg of background etorphine equivalents/ml in raw urine and was 100 pg/ml in hydrolyzed urine. The /sup 125/I-RIA was capable of detecting etorphine equivalents in urine above these background values. Etorphine equivalents were detected in equine urine samples for about 7 days after 4 mares were dosed with 0.22 microgram of etorphine/kg of body weight, IV. The stability of etorphine in urine from these mares was evaluated. Urine from these dosed mares was held in constant -20 C storage, and aliquots were repeatedly frozen and thawed. When analyzed for etorphine equivalents using an /sup 125/I-RIA, etorphine and its metabolites in urine samples were stable for less than or equal to 38 days if continuously frozen and also were resistant to repeated freezing and thawing.

• Research Organization: Univ. of Kentucky, Lexington (USA)
• OSTI ID: 7002439
• Journal Information: Am. J. Vet. Res.; (United States), Journal Name: Am. J. Vet. Res.; (United States) Vol. 49:5; ISSN AJVRA
• Country of Publication: United States
• Language: English

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550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANALGESICS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HORSES
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
NARCOTICS
NUCLEI
ODD-EVEN NUCLEI
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
REACTION KINETICS
TRACER TECHNIQUES
URINE
VERTEBRATES
WASTES