Development of corpus luteum susceptibility to an analog of prostaglandin F2α, throughout the luteal phase in llamas (Lama glama)

Autor: Carolina Paula Bianchi, M.A. Benavente, MV Cavilla, Marcelo A. Aba, E. Jorgensen
Rok vydání: 2011
Předmět:
Zdroj: Animal reproduction science. 131(3-4)
ISSN: 1873-2232
Popis: The aim of the present study was to evaluate the susceptibility of the corpus luteum to d-cloprostenol (synthetic analog of PGF 2α ) 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 −1 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 2α until Day 4 after induction of ovulation, being partially sensitive by Day 5 and fully responsive to PGF 2α , by Day 6 after induction of ovulation.
Databáze: OpenAIRE