• Title/Summary/Keyword: dybowskii

Search Result 101, Processing Time 0.04 seconds

Roles of Theca and Granulosa Cells in Follicular Steroidogenesis in Rana dybowskii (북방산 개구리 여포의 스테로이드생성과정에 협막세포와 난구세포의 역할)

  • 안련섭;소재목;권혁방
    • The Korean Journal of Zoology
    • /
    • v.39 no.3
    • /
    • pp.273-281
    • /
    • 1996

  • Previously, we have proposed a two-cell type model for follicular steroidogenesis inamphibians with Rana nigromacu lota. Present experiments were carried out to ascertain whether the model Is applicable to R. dybowskii. The role of theca layer were also reassessed by using granulosa cell-free pure theca layer (P-THEP). Theca/epithelium (THEP) layers, P-THEP layers, and granulosa cell enclosed-oocytes () were obtained from ovarian follicles of R. dybowskii by microdissection. Intact follicles (IFs) and different types of tissues were cultured for 6 hour in amphibian Ringer's m the presence or absence of FPII (0.05 gland/mi) or various steroid precursor (100 ng/ml). The amounts of product steroids converted by the components were measured by RIA. Exogenously added pregnenolone (P5) resulted in a marked increase in progesterone (P$_4$) by GCEOs (2143 pg/follicle) and IFs (2346 pg/follicle) but a smaller increase in P4 by THEP layer (495 pg/follicle). Addition of P$_4$ increased 17 a-hydroxyprogesterone (17 $\alpha$-OHP$_4$) levels by GCEOs (1118 pg/follicle) and IFs (1333 pg/follicle) but less by THEP layer (290 pg/follicle). However, much less amounts of P$_4$ or 17 $\alpha$-OHP$_4$ were producad by P-THEP layers than THEP in the presence of P5. Exogenous 1 7$\alpha$-OIIP$_4$ increased androstenedione (AD) levels by GCEOs (1415 pg/follicle) and IFs (561 pg/follicle) but not by THEP layers. In contrast, addition of AD resulted m a marked increase in testosterone (T) levels by TIIEP (2594 pg/follicle) and IFs (2223 pg/follide) but much less by GCEOs (339 pg/follicle). Exogenous T increased estradiol (E$_2$) levels by GCEOs (551pg/follicle) and IFs (887 pg/follicle), but not by THEP layer (<10 pg/follicle). Without addition of FPH or steroid precursors, very low or nondetectable levels of steroids were produced (< 20 pg/follicle) by all the types of follicular components examined. The data presented here indicate that the two-cell type model based on the study with R. nigromacu Iota is applicable to R. dybowskii and also suggest that the minor pathway, which convert P5 to 17$\alpha$-OHP$_4$, is not present in theca layer.

  • PDF

Effect of Heavy Metal Ions on the Oocyte Maturation of Frog, Rana dybowskii in vitro (중금속 이온이 산개구리 난자성숙에 미치는 영향에 관한 연구)

  • 고선근;이두표
    • Korean Journal of Environment and Ecology
    • /
    • v.11 no.3
    • /
    • pp.310-315
    • /
    • 1997

  • In oreder to know the effect of the oocyte maturation with several heavy metal ions(Cd$^{2+}$, Hg$^{2+}$, Cu$^{2+}$, Pb$^{2+}$) on frog(Rana dybowskii) by FPH(Frog pituitary homogenate: 0.1 p.e./ml) in vitro, oocytes were cultured for 20 hours and exanimed the maturation rates with exposure of various comcentrations of those ions. The results showed that Cd$^{2+}$ at concentration of 0.1 ppm suppressed the maturation of the oocytes, while Hg$^{2+}$, Cu$^{2+}$ and Pb$^{2+}$ suppressed them significantly at 1 and 5 ppm respectively. To examine the reversibility of the inhibitory effects, the oocutes were exposed to the metal ions only for 3 hours and transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the ions when they were exposed to 1 ppm of Cd$^{2+}$ for 3 hours and not available to 2.5 ppm. The effect of 2.5 ppm of Hg$^{2+}$, Cu$^{2+}$, Pb$^{2+}$ were also reversible and not available to 5 ppm for 3 hours exposure. From the abave results, it reveal that heavy metal ions in this study suppressed the maturation of oocytes at relatively low concentration. Therefore the oocyte culture system can be used as a useful tool to evaluate the toxicity of the pollutants in envirment.

  • PDF

Role of cAMP in the Regulation of Progesterone Production and Secretion by Frog (Rana dybowskii) Follicles in vitro (북방산 개구리(Rana dybowskii)의포의 프로젝트론 생서에 대한 cAMP의 조절작용)

  • 권혁방;안연섭;김지열;윤용달
    • The Korean Journal of Zoology
    • /
    • v.31 no.3
    • /
    • pp.177-184
    • /
    • 1988

  • The pattern of progesterone production and secretion of frog(R. dybowskii) follicles was investigated in follicle culture in vitro. Involvement of cAMP in the regulation of the steroid production by the follicles was also investigated by manipulating endogeneous cAMP level with forskolin and/or 3-isoburyl- 1 - methylxanthine(IBMX). Endogeneous follicular progesterone level increased rapidly in one hour of culture by treatment of frog pituitary homogenate(FPH) and reached peak level at 2 hours or later. But the absolute amount of progesterone produced (60-300 pg/follicle) or the peak time of the honnone level was different between individual animals. Basal level of progesterone in untreated sister follicles was very low (around 10 pg/follicle) and nearly undetectable in most cases regardless of culture lime. Secretion level of progesterone by the follicles obtained by measunng the honnone in the culture media was just the reflection of the intrafollicular level. Exogeneously added forskolin, an adenylate cyclase stimulator, and/or IBMX, a phosphodiesterase inhibitor, could mimic FPH action in terms of progesterone production and secretion. Thus, it seems clear that FPH regulates progesterone production via cAMP system in the follicle cells.

  • PDF

UV Effect on the Number of Primordial Germ Cells in the Embryo of Rana dybowskii (자외선이 산개구리 (Rana dybowskii) embryo의 시원생식세포 수에 미치는 영향)

  • 정해문;김원숙
    • The Korean Journal of Zoology
    • /
    • v.27 no.1
    • /
    • pp.13-24
    • /
    • 1984

  • The fertilized eggs of Rana dybowskii were irradiated with UV (254 nm wave length) on the vegetal hemisphere to investigate the effects on the primordial germ cells (PGCs) and axis formation. The investigations were carried out in two ways; namely time course and UV dose. Up to 1,600 $ergs/mm^2$ of UV dose, irradiated at 60 min. after fertilization, there was no effect on the PGC number. However, the number of PGC comparing with that of unirradiated control was decreased more than 40%. As the amount of irradiation was increased, the number of PGC was inversely declined. The maximal dose of irradiation which eliminates PGC completely without inducing any axis abnormality was 4,800 $ergs/mm^2$. If the eggs were irradiated earlier with this amount the severer effect could be obtained. Thus the UV effect on the PGC number was most effective when irradiated by 60 min. post fertilization. Thereasfter stage. At UV doses over 9,600 $erge/mm^2$ other effects start to appear; namely abnormalities of nerual tube and axis formation. Therefore, comparative study on the UV sensitivity of PGC and axis formation was carried out. It was revealed that UV effect on the axis was drastically decreased at the time of $0.7\\sim0.8$ between fertilization and 1st cleavage, while the germ plasm was sensitive to UV until 4 cell stage.

  • PDF