%0 Journal Article %A HE Qian %A WANG Lihong %A YANG Fan %A ZHANG Jinguo %A ZHANG Li %T Urinary estradiol and progesterone dynamics in captive Asian elephants %D 2007 %R %J ACTA THERIOLOGICA SINICA %P 74-79 %V 27 %N 1 %X Two adult female Asian elephants at the Beijing Zoo are not known to have ever come into estrus. In order tounderstand possible reasons for this,we studied variation in urinary estradiol and progesterone levels of these 2 non-oestrus females,as well as of a pregnant female at the zoo,via radioimmunoassay from December 2003 to March 2005. For the pregnant female, progesterone increased abruptly one week before parturition and remained at a low level afterwards. Estradiol began at a high level,decreased suddenly one week before parturition, and remained at a low level until the end of the study. Urinary progesterone and estradiol levels in the non-estrus elephants was notably lower than in the pregnant elephant, and displayed no obvious periodic fluctuation. We hypothesize that ovaries in these 2 elephants were inactive, resulting in lack of hormone fluctuation and lack of estrous.
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