Development of corpus luteum susceptibility to an analog of prostaglandin F_2伪, throughout the luteal phase in llamas (Lama glama)

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• 作者：C.P. Bianchi ; ^{cbianchi@vet.unicen.edu.ar} ; M.V. Cavilla ; E. Jorgensen ; M.A. Benavente ; M.A. Aba
• 关键词：Corpus luteum ; Luteolysis ; Prostaglandin ; Llamas
• 出版年：2012
• 期刊代码：8_03784320
• 类别：abs
• 出版时间：April, 2012
• 卷：131
• 期：3-4
• 页码：199-203
• 文件大小：273 K

摘要

The aim of the present study was to evaluate the susceptibility of the corpus luteum to d-cloprostenol (synthetic analog of PGF_2伪) throughout the luteal phase in llamas. Female llamas (n = 43) were induced to ovulate by GnRH injection in the presence of an ovulatory follicle and randomly assigned into one of six groups: control and treated with an injection of d-cloprostenol on Day 3, 4, 5, 6 or 8 post GnRH. Blood samples were collected to determine plasma progesterone concentrations. There was no effect of treatment on animals injected on Day 3 or 4 post-GnRH. In animals treated on Day 5, different responses were observed. No effect of treatment was recorded in 27%of the animals whereas 55%of the llamas showed a transitory decrease followed by a recovery in plasma progesterone concentrations after d-cloprostenol injection, indicative of a resurgence of the corpus luteum, extending the luteal phase a day more than in control animals. In the remaining 18%of the animals injected on Day 5, (corresponding to those exhibiting the greatest plasma progesterone concentrations at the day of injection), complete luteolysis was observed. Plasma progesterone concentrations decreased to below 1 ng ml^鈭? 24 h after d-cloprostenol in llamas injected on Day 6 or 8 post-GnRH. In conclusion, the corpus luteum of llamas is completely refractory to PGF_2伪 until Day 4 after induction of ovulation, being partially sensitive by Day 5 and fully responsive to PGF_2伪, by Day 6 after induction of ovulation.