Development and evaluation of a rapid enzyme-immunoassay system for measurement of the urinary concentration of estrone-3-glucuronide in a female giant panda (Ailuropoda melanoleuca).

To detect estrus for reproductive management, and to determine the relationship between urinary estrogen and estrous behavior, in a female giant panda, we developed and evaluated a rapid enzyme immunoassay (EIA) system for urinary Estrone-3-glucuronide (E1G) using commercial reagents. The developed EIA system took only around 3 hours, including all procedures to obtain a result. It indicated good reproducibility (intra-assay CV of 5.16%, interassay CV of 15.4%) and sensitivity (lowest standard concentration was 0.0156 ng/ml) for measurement of the urinary concentrations of E1G in the giant panda. There was a positive correlation (r=0.934) with the data for estrone (E1) in the same samples, as measured by radioimmunoassay (RIA) performed in a commercial laboratory. The changes in the E1G concentrations were almost synchronous with the changes in E1 assayed by RIA in urine collected during 4 consecutive estrous seasons. The dynamics of urinary E1G measured by this system highly correlated with the occurrence of the presenting estrous behavior in the giant panda. The above results indicate that this assay system may be normally, rapidly and practically used for measurement of the urinary concentration of E1G in the giant panda.