Roles of Cyclic AMP and Protein Kinase C in the Oocyte Maturation and Ovulation in Crucian Carp, Carusius auratus

붕어 난모세포의 성숙과 배란 과정에서 cyclic AMP와 protein kinase C의 역할

Gonadosomatic index (GSI) of the crucian carp (Carassius auratus) was investigated to clarify annual reproductive cycle from February in 1992 to October in 1994. The values of GSI were high with individual variation from April to July which period was coincided with the breeding season of fish. The GSI was very low in August and September, when follicular atresia developed in the ovaries. GSI value began to increase in October and reached a peak around the following March, which indicated that ovarian follicles may grow during this period. Human chorionic gonadotropin (HCG 10 IU), $17\alpha$, 20\beta-dihydroxyprogesterone\;(1-100{\mu}g/ml)$ and phorbol 12-myristate-13-acetate (TPA, protein kinase C activator, 0.1-10${\mu}M$) induced germinal vesicle breakdown (GVBD), but $4\alpha-phorbol$ 12, 13- didicanoate ($4\alpha-PDD,\;phorbol\; ester\;analogue,\;25{\mu}M$) did not induce germinal vesicle breakdown in the follicular oocytes. Prostaglandin $F_{2\alpha}$ $(0.1-10 {\mu}g/ml)$ and TPA $(0.1-10 {\mu}M$ induced ovulation of the oocytes, but $4\alpha-PDD$ $(25{\mu}M)$ did not induce ovulation of the follicles. $17\alpha-hydroxyprogesterone$ production was examined from the isolated follicles to investigate the steroid production ability in the crucian carp ovaries. HCG (1 lU, 10 lU) and forskolin (adenylate cyclase activator, 0.1-10 ${\mu}M$) stimulated $17\alpha-hydroxyprogesterone$ production. The time course of HCG (10 lU) and forskolin $(10\;{\mu}M)$ stimulated $17\alpha-hydroxyprogesterone$ production within 3 hours, the elevated levels were maintained during the rest of the culture period. The data indicates that cyclic AMP and protein kinase C may play important roles in the oocyte maturation and ovulation in crucian carp.

붕어의 년 생식주기를 밝히기 위해 1993년 2월부터 1994년 10월까지 gonadosomatic index (GSI)를 조사하였다. GSI는 4월부터 7월까지는 높은 수준을 나타내며 개체간에 편차가 큰 것으로 보아 이 기간이 산란기임을 보여준다. 8월부터 9월까지는 년중에서 가장 낮은 수준이며 이때 난소내 여포는 퇴화가 진행 중이었다 10월부터 GSI 값은 증가하여 이듬해 3월에 최대치를 보였다. Human chorionic gonadotropin (HCG 10 lU), $17\alpha$, 20\beta-dihydroxyprogesterone\;(1-100{\mu}g/ml)$ 및 phorbol 12-myristate 13-acetate (TPA, protein kinase C activator, 0.1-10${\mu}M$)는 인공배양 시 난모세포의 성숙을 유도하였으나 $4\alpha-phorbol$ 12, 13-didicanoate ($4\alpha-PDD$, phorbol ester analogue, $(25{\mu}M$)는 성숙을 일으키지 않았다. 또한, HCG (10 IU), prostaglandin $F_{2\alpha}$ (0.1-10${\mu}g/ml$) 및 TPA (0.1-10${\mu}M$)는 난모세포의 배란을 유도하였으나 $4\alpha-PDD$$(25\;{\mu}M)$에 의해서는 배란이 일어나지 않았다. 여포세포의 $17\alpha-hydroxyprogesterone$은 HCG (1 IU, 10 IU) 및 forskolin (adenylate cyclase activator, 0.1-10 ${\mu}M$)에 의해 생성이 촉진되었으며 HCG (10 IU) 및 forskolin $(10 {\mu}M)$에 의한 time course 는 3시간 내에 생성량이 증가하여 시간경과에 따른 유의한 차이는 보이지 않았다. 이러한 결과를 종합하면 cyclic AMP와 protein kinase C 는 어류의 난모세포의 성숙과 배란과정에 매우 중요한 역할을 담당하는 것으로 생각된다.