PARENT SESSION

(T323) TREATMENT OF PROGESTERONE INCREASES AKT PHOSPHORYLATION IN BOAR SPERMATOZOA.

Jang, Sunphil¹, Yi, Lee S. H.¹, ¹ Sungkyunkwan University, Suwon, Korea

ABSTRACT- Progesterone (P), known as a physiological inducer of acrosome reaction (AR) in various mammalian spermatozoa, was implicated to exert its effects via membrane bound progesterone receptor, which in turn activates a specific signal transduction pathway inside spermatozoa. Despite the intense investigation, however, the signal transduction mechanism involved in P-induced AR is poorly understood. Recently, Akt, a signaling molecule related to the cell survival/apoptosis in PI3K/Akt signaling pathway has been reported that it may be involved in the signal transduction pathway of capacitation and AR in human spermatozoa, in which AR was induced by lysophosphatidylcholine in the presence of inhibitors of various kinases. In the present study, we examined the presence of Akt and its involvement in the P-induced AR signal transduction pathway in boar spermatozoa. Upon western blot analysis, 61kDa Akt was clearly detected in boar spermatozoa. Furthermore, when analyzed by the antibody against phosphorylated Akt (p-Akt), the level of p-Akt increased in a dose-dependent manner in capacitated boar spermatozoa upon P treatment, while uncapacitated spermatozoa did not show any significant phosphorylation. The phosphorylation of Akt seemed to increase up to 15 min after P treatment and then dephosphorylated. This study clearly demonstrated that Akt is present in boar spermatozoa and involved in P-induced AR signal transduction pathway through phosphorylation/dephosphorylation mechanism.

KEY WORDS: progesterone, Akt, acrosome reaction, spermatozoa