• YAKHAK HOEJI
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• v.43 no.3
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• pp.378-384
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• 1999

Retinoic acid (RA) and dibutyryl cyclic AMP (dbcAMP) induce the differentiation of the multipotent embryonic carcinoma cell line, F9 cells, into parietal endoderm like cell. The F9 cells are highly proliferative doubling approximately 12 hourse. S Phase is predominant, lasting 10 hours and G2/M phase occupies most of the remaining cycle (2 hours) and G1 phase is nearly non-existent. In this study, we showed the effect of RA and dbcAMPon the cell cycle associated molecules (especially around G1 phase) during F9 cell differentiation. Differentiation of F9 cells was induced by the combined addition of RA ($10^{-7}M$) and dbcAMP (0.5mM), and cells were harvested daily up to 4 days. Flow cytometric analysis showed the prolongation of G1 phase around 30 hours after induction. Western blot analysis revealed that the amount of cyclin D1 and cdk2 were increased at day 4. However, histone H1 kinase activity of cdk2 was decreased. These data strongly suggest that RA and dbcAMP induce the growth arrest of F9 cells at G1 phase by decreasing the activity of cdk2, although they have increased the protein contents of cyclin D1 and cdk2. The reason for the discrepancy between the H1 kinase activity and protein contents are not clear yet.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.194-197
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• 1986

Malonate kinase and isocitrate lyase were induced in Acinetobacter calcoaceticus grown on malonate as a sole carbon source but repressed by succinate. The induction of those two enzymes was stimulated by dibutyryl cyclic adenosine 3', 5'-monophosphate, indicating that the expression of their genes for those enzymes is dependent on cyclic adenosine 3', 5'-monophosphate.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.127-133
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• 1990

Dibutyryl-cyclic AMP (db-cAMP) and forskolin were used to investigate vasodilating mechanism of cAMP in rabbit aorta. Db-cAMP and forskolin inhibited the development of contractile tension induced by norepinephrine (NE) concentration-dependently. However, high $K{^+}-induced$ contractile tension was inhibited less effectively by db-cAMP and forskolin. Db-cAMP and forskolin inhibited $^{45}Ca^{2+}$ uptake increased by NE. Forskolin seemed to inhibit $^{45}Ca^{2+}$ uptake increased by high $K{^+}$, but this inhibition was not significant statistically. Db-cAMP inhibited $Ca^{2+}-transient$ contraction by NE in $Ca^{2+}-free$ solution. In conclusion, it seems that cAMP blocks $Ca^{2+}$ influx through receptor operated $Ca^{2+}$ channels (ROCs), but that the effect of cAMP on $Ca^{2+}$ influx through voltage gated $Ca^{2+}$ channels (VGCs) is not clear in this experiment. Furthermore, cAMP is likely to inhibit calcium release from the intracellular stores.

• The Korean Journal of Zoology
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• v.18 no.1
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• pp.19-26
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• 1975

自記放射法을 이용하여 dbcAMP와 theophylline이 未成熟卵子의 RNA合成에 미치는 영향을 관찰하였다. 培養中인 未成熟卵子의 RNA合成은 dbcAMP와 theophylline에 의하여 抑制를 받았다. dbcAMP나 theophylline은 培養液(modified Krebs-Ringer bicarbonate solution)內에 100 $\\mu$g/ml 정도 들어 있으며 핵막(germinal vesicle)의 붕괴 되지 못하고 그대로 存在하며 그동안의 RNA合成은 극히 억제된 채로 남아 있다. 그러나 培養을 시작하여 2$\\sim$3時間後, 즉 핵막붕괴가 끝난 다음에 이들 억제물질을 배양액에 添加하면 正常卵子와 같이 성숙분열이나 RNA合成이 억제 됨이 없이 진행된다. 24時間동안 dbcAMP나 theophylline으로 성숙이 억제 되었던 卵子도 이들 억제물질을 제거하면 즉시 成熟分裂이 진행되며 RNA合成도 正常的으로 일어난다. 이런 結果로 미루어 dbcAMP등의 RNA合成 抑制機作에 한 가지 가능성을 추측할 수 있다. 즉 dbcAMP나 theophylline의 처리에 의해 細胞質內 cAMP의 농도가 높아지고 이 cAMP는 핵막붕괴나 染色質의 응집에 관여하는 단백질 合成을 誘導할 mRNA合成을 억제하며 이 때문에 卵子는 핵을 보유한채 그대로 남아 있는 것이다.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.3
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• pp.143-147
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• 1988

In order to investigate the mechanism of regulation of progesterone production, quail were hypophysectomized at various times during the ovulation cycle, and granulose cells were isolated from follicles 4 hr after the operation. They were incubated in vitro at $40^{\circ}C$ with or without LH or dibutyryl cyclic AMP, and the amounts of progesterone produced during 3 hr of incubation were measured by radioimmunoassay. Hypophysectomy at 8 hr or 20 hr before the predicted time of ovulation caused a reduced responsiveness of F1 granulosa cells to exogenous LH or dibutyrul cyclic AMP. Although hypophysectomy at 24 hr before ovulation caused a slight reduction of responsiveness of F1 granulosa cells, the reduction of the progesterone production during the incubation without any stimuli was prominent by the sham operation. These results suggest that the presence of pituitary gland influences the ability of the granulose cells to produce progesterone in response to LH or dibutyryl cyclic AMP.

• The Korean Journal of Zoology
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• v.18 no.1
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• pp.27-40
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• 1975

dbcAMP와 theophylline이 난자의 성숙을 억제하는 기작과 난자내 glycogen 함량과의 관계를 밝혀보기 위하여 실험한 결과는 다음과 같다. 1. 생쥐 여포난자의 PAS 양성물빌은 glycogen이며 핵의 성숙분열이 진행됨에 따라 glycogen의 함량은 감소한다. 2. dbcAMP나 theophylline에 의해 핵의 성숙이 억제된다 하더라도 난자내의 glycogenolysiss는 촉진된다. 이에 반해 핵분열이 일어나지 않은 난자는 배양이 진행되더라도 glycogen을 그대로 유지하고 있다. 일단 dbcAMP나 theophylline에 의해 성숙이 억제되었던 난자가 성숙과정에 들어가려면 다시 glyconeogenesis가 일어나 세포질내의 glycogen의 양이 회복하며 이때의 glycogen은 핵성숙과 더불어 소모된다. 3. Glycogen의 회복은 배양액내의 glucose 유무에 관계없이 이루어지며 따라서 이는 난자내 glucose 혹은 다른 전구물질에 의해 이루어지리라고 추측된다. 4. 결국 dbcAMP나 theophylline은 난자내 cAMP의 양을 증가시켜 glycogen의 소모를 일으키는 것으로 생각되며, glycogenolysis와 난자의 핵 성숙과정이 별개로 진행되기는 하지만 성숙의 요건은 일정량 이상의 glycogen이 함유되어 있어야 한다는 것을 알게되었다.

• Toxicological Research
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• v.4 no.1
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• pp.47-53
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• 1988

Cholera toxin and dibutyryl cyclic adenosine 3', 5'-monophosphate(db-cAMP) increased the rate and number of infections units produced in the in vitro reactivation of latent herpes simplex virus, whereas adenosine diminished them. cAMP concentration in latently infected trigeminal ganglia of mice was greatly increased by cholera toxin but was not affected by adenosine.

• The Korean Journal of Zoology
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• v.18 no.2
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• pp.87-101
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• 1975

Electron microscopic studies on the ultrastructure of the mouse oocyte were made to investigate the inhibition of germinal vesicle breakdown by dibutyryl cAMP. The nuclear membrane of the dibutyryl cAMP-treated oocyte is characterized by a decreased degree of folding, maintains the normal double membrane structure, and shows an increased occurrence of the nuclear pore. It is suggested that these may be related to the suppression of the maturation of oocytes at the germinal vesicle. Mitochondria in the control cell were shown to be spread evenly throughout the cytoplasm and structurally underdeveloped or transitionary having little cristae development. On the contrary, mitochondria in the treated oocyte were found to be localized mainly around the nucleus and to show a greater extent of cristae development. The oocyte treated with dibutyryl cAMP appears to have fewer and structurally simpler lysosomes as compared to the control. The Golgi complex in the control oocyte exhibits the typical granular and lamellar structure, whereas that in the treated cell is poorly developed. Many multivesicular bodies, tonofilaments, and free ribosomes were observed in the control as well as in treated cells. The microvilli become structurally irregular, and a development of the perivitelline space is apparent in the treated oocyte. It is concluded that there is no basic difference in the ultrastructure between the oocytes treated with dibutyryl cAMP for 24 hours in the medium and those collected directly from the follicle. However, the finding that dibutyryl cAMP induces a development of more pores along the nuclear membrane strongly suggests the possibility that this compound inhibits the maturation of oocytes by influencing the permeability of the nuclear membrane.

• The Korean Journal of Zoology
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• v.32 no.3
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• pp.290-303
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• 1989

The activities of $\beta$-glucosidase, $\beta$-glucuronidase and N-acetyl-$\beta$-glucosaminidase were measured to investigate the relationships of them to sexual maturity. Peritoneal injections of testosterone and dibutyryl cAMP to rats were carried out. As a result, the activities of $\beta$-glucosidase and N-acetyl-$\beta$-glucosaminidase were significantly decreased from the third day and that of P -glucurondiase on the seventh day in the castrated groups. In addition, ihe activities of these three enzymes were significantly increased in the testosterone treated groups for 7 days. In case of dbcAMP injection, the activities of these three enzymes were similar to those of castrated groups or had a tendency to be decreased. On electron microscopic examination, principal cells, basal cells and narrow cells were observed in all regions of epididymis. Principal cells were general forms of columnar epithelial cells. Narrow cells had a number of small vesicles and light cells showed low electron density in comparison to other epithelial cells in cauda epididymis. Halo cells were migrating leucocytes btween epithelial cells.

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.167-181
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• 1991

The present study was an attempt to investigate the effect of forskolin on secretion of catecholamines (CA) evoked by Ach, excess $K^+$, DMPP, McN-A-343 and caffeine from the isolated perfused rat adrenal glands and to elucidate its mechanism of action. The perfusion with forskolin (1.0 uM) for 1 min into the adrenal vein enhanced markedly the secreation of CA evoked by Ach (50 ug), excess $K^+$ (56 mM) DMPP (100 uM) and by caffeine (0.3 mM) but did not that by McN-A-343. Forskolin alone did not potentiate the CA secretion. Moreover, forskolin augmented the CA release evoked by the above same stimulation even in the absence of extracellular calcium. The 1 min perfusion of 300 uM-dibutyryl cyclic AMP (DBcAMP), which is known to increase cyclic AMP levels, led to enhancement of Ca secretion evoked by Ach, excess $K^+$ and DMPP but did not that by McN-A-343 and caffeine. DBcAMP by itself also did not augment the CA secretion. In the calcium-free medium DBcAMP significantly enhanced the CA secretion by the same stimulation, except for the case of McN-A-343. These experimental results suggest that forskolin activates adenylate cyclase, resulting the elevation of cyclic AMP which may potentiate cholinergic nicotinic receptor-mediated and also depolarization-dependent CA secretion and that it may alter the intracellular calcium homeostasis in the rat adrenal glands.