Activation by Stimuli of Sperm Penetration in Bovine Oocytes Treated with Higher Concentration of BAPTA/AM.

Shojo, Aiko; Shimada, M.; Takato, Tsuyoshi

doi:10.1274/jmor.17.96

Cited by 1 publication

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“…2+ chelator BAPTA-AM BAPTA/AM treatment was based on the procedures reported in our previous study [19]. COCs were loaded with 50 µM BAPTA-AM for 1 hr at 39°C.…”

Section: Treatment Of Coc With Camentioning

confidence: 99%

Both Ca2+-Protein Kinase C Pathway and cAMP-Protein Kinase A Pathway are Involved in Progesterone Production in FSH- and LH-stimulated Cumulus Cells during In Vitro Maturation of Porcine Oocytes

et al. 2002

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Abstract:We investigated the role of cAMP-Protein kinase A pathway and Ca 2+ -Protein kinase C pathway w hich were activated by FSH and/or LH in the progesterone production by cumulus cells during in vitro m a t u r a t i o n o f p o r c i n e o o c y t e s . T h e l e v e l o f progesterone in the medium in which COCs had been cultured for 24 hr without FSH was 7.8 ± 1.5 ng/ml. The addition of FSH significantly increased the progesterone level in a dose-dependent fashion during 24-hr cultivation of COCs; a plateau was detected in 0.02 µg/ m l , b u t n o si g n i f i ca n t i n cr ea s e i n t h e l ev e l o f progesterone was observed in the medium in which COCs had been cultured for 24 hr with 1 or 10 µg/ml LH. When COCs were cultured with both 0.02 µg/ml FSH and 1.0 µg/ml LH for 24 hr, the maximal level of progesterone was detected. The effects of the addition of LH to FSH-supplemented medium on the response of cumulus cells were affected by the suppression of the Ca 2+ -Protein kinase C pathway. Forskolin-induced p r o g e s t e r o n e p r o d u c t i o n w a s n o t a f f e c t e d b y suppression of the Ca 2+ -Protein kinase C pathway but was reduced by Protein kinase A inhibitor. These results showed that Ca 2+ -Protein kinase C pathway in cumulus cells stimulated by FSH, enhanced LH-induced progesterone production via a cAMP-Protein kinase A dependent pathway. [4][5][6]. When porcine COCs were cultured with LH, FSH, and progesterone synthesis inhibitor, almost complete inhibition of both progesterone production and GVBD was detected, and this inhibitory effect on GVBD was overcome by additional progesterone [6]. Therefore, progesterone secreted by cumulus cells is associated with meiotic maturation of porcine oocytes. Moreover, we also showed that the binding of progesterone to its receptor induced the disappearance of connexin-43 in cumulus cells, resulting in closing gap junctional communication in outer layers of cumulus cells [6,7]. In pigs, a significant positive correlation was seen between the proportion of GVBD oocytes and that of COCs exhibiting a loss of the gap junctional communication between the cumulus cells in outer layers [8,9]. Thus, the binding of progesterone to its receptor in cumulus cells exhibits GVBD in porcine oocytes, through closing gap junctional communication in outer layers of cumulus cells.The addition of adenylcyclase activator, forskolin, to the maturation medium has been reported to stimulate progesterone production in cumulus cells concomitantly with an increase in the cAMP level in the cells [10].

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“…2+ chelator BAPTA-AM BAPTA/AM treatment was based on the procedures reported in our previous study [19]. COCs were loaded with 50 µM BAPTA-AM for 1 hr at 39°C.…”

Section: Treatment Of Coc With Camentioning

confidence: 99%