• 한국수정란이식학회지
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• 제5권1호
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• pp.1-20
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• 1990

Follicular atresia is a universal and characteristic phenomenon of both non-mammalian and mammalian vertebrates. Generally it is estimated that greater than 99% of follicles become atretic in higher domestic animals and human. The number of selected follicles developing to the preovulatory stage are thus fewer. Follicles can become atretic at any stage of development. The previous studies emphasized on descriptive and retrospect aspects of a limited population of the fully grown preovulatory follicle. The main efforts in ovarian physilogical researches are focused on follicular development culminating in ovulation but recent advances have resulted in a better understanding of atresia. Nowadays, recent studies are concentrated on the induction of atresia in a selected population of follicles and of the associated cellular, endocrine, biochemical and molecular changes. The factors initiating atresia and follicle selections are worthy of investigations. Another intriguing question is whether one can predict when a follicle will become atretic, i.e., what biochemical markers indicate that a follicle is destined for atresia. It is generally agreed that atretic process may vary even in antral follicles at different stages of their differentiations and among species. The dicisive factors are follicular responsiveness and the hormonal milieu. Some generalizations can be made on the basis of experimental induction of atresia. Alteration of the pattern of follicular steroid production is associated with the initiation stage of atretic process. Atresia appears to be a process unfolding gradually and affecting progressively in increasing number of functions and components of the follicle. The oocyte may be the latest to be afflicted in the atretic process. The high steroidogenic activity of atretic follicles lends support to the notion that atresia is not necessarily a degenerative process and that atretic follicles may play an essential role in ovarian physiology. The simultaneous occurence of growth and atretic processes may render the search for regulatory mechanisms involved in atresia difficult extremely. The questions such as how follicles are selected to undergo ovulation rather than atresia or what the mechanism of atresia is remain unanswered. However, the factors regulating or modifying ovarian hormonal milieu for the initiation of follicular growth and maturation or of atresia are being elucidated.

• 대한수의학회지
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• 제39권1호
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• pp.27-33
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• 1999

In the mammalian ovary, follicular development and atresia continuously occur during the reproductive cycles. Follicular atresia occurs through granulosa cell apoptosis. Apoptosis is known as the physiological cell death, which is regulated by bcl-2 gene family. In the bcl-2 gene family, bcl-2 and bcl-xLong are known as inhibitors of apoptosis, whereas bax and bcl-xShort are known as inducer of apoptosis. We thought that bcl-2 protein is associated with follicular development and atresia. But it is not known that the distribution of cells containing bcl-2 protein during follicular development and atresia. Therefore, to examine the distribution of cells with bcl-2 protein during ovarian follicular development and atresia, the immunohistochemistry was used in the rat ovary. Bcl-2 immunoreactivity was localized in the interstitial cells, theca externa cells and granulosa cells around of antrum. All positive signals were observed in the cytoplasm of these cells. Positive signals were strongly observed in the interstitial and theca externa cells of growing antral follicles. While, positive signals were weakly observed in these cells from atretic antral follicles. Positive signals were very weakly observed in the granulosa cells of growing and atretic antral follicles. According to these data, we suggested that bcl-2 proteins which were strongly expressed in the interstitial cells and theca externa cells of growing antral follicles inhibit follicular atresia. And we purposed that bcl-2 proteins regulated follicular development and atresia through the action of bcl-2 gene family.

• Clinical and Experimental Reproductive Medicine
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• 제13권1호
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• pp.39-51
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• 1986

This experiment has been done to evaluate the relationship between the follicular atresia and the protein patterns on electrophoreais of the follicular fluids in porcine ovary. The protein concentration of the follicular fluids was lower than that of serum, and gradually decreased as the follicle siae became larger. The number of protein bands of follicular fluid on electrophoresis was less than that of serum, and gradually increased as follicle size became larger. Three specific bands were detected on disc PAGE and one band(M W. 75,000) on SDS PAGE in the follicular fluids, while not in serum. One band (A) at ${\beta}$-globulin region on disc PAGE became heavier, as follicles became atretic. Two bands less than(M. W. 20,000) were detected only in the large follicular fluid. Another band(M. W. 43,000) was not detected in necrotic group, whereas all other groups showed it. It could be concluded that the component and composition of the proteins follicular fluids changes according to the follicular size during atresia. Therefore detection of the changing pattern of proteins in the follicular fluid can be used as a basic criterion for the identification of follicular atretic stage.

• Clinical and Experimental Reproductive Medicine
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• 제25권2호
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• pp.179-187
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• 1998

In mammal, lots of follicles start simultaneously their growth but only a few oocytes are ovulated in every sexual cycles. Most of matured and grown oocytes are destined to degenerate by atresia. However, the molecular and physiological mechanisms are not elucidated yet. The present study was designed to establish an induction method of follicular atresia with ketamine or pentobarbitone and evaluate the effect of these anesthetics on oocyte maturation and granulosa cell apoptosis of the mouse ovarian follicle. The percentages of degenerated oocyte and apoptotic granulosa cell in ketamine treated groups were significantly higher than that in controls (58.9% vs 33.5%, p<0.01, degeneration; 44.9% vs 26.6%, p<0.01, apotosis). Futhermore, it was revealed that the concentrations of progesterone in both groups were markedly higher than that in control. In cunclusion, it is considered that ketamine induce an atresia as pentobarbitone, and may be useful for inducing follicular atresia.

• 한국가축번식학회지
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• 제16권2호
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• pp.165-173
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• 1992

In order to study the mechanism of follicle growth and maturation, and also to supplement the criteria identifying the follicle state of normal of atretic, the histochemical investigation on the ovarian follicles according to the ovarian cycle of mouse, rat and pig has been done. The intercellular space of granulosa cells, especailly Call-Exner body, and follicular fluid in the antrum showed positive to PAS, and blue stain by trichrome dye. The resutls suggest that the mucous polysaccharide was synthesized by the granulosa cells, and secreted into the antrum through Call-Exner body so as to be the components of the follicular fluid as the follicles proceeded to growth and maturation. The further the follicles proceeded to atresia the more densely their theca externa were stained blue by follicles proceeded to atresia the more densely their theca externa were stained blue by trichrome dye, and the more densely the granulosa cells were stained red by oil red 0 dye. Therefore, these staining methods can be applied to the criteria identifying the follicle atresia.

• Clinical and Experimental Reproductive Medicine
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• 제16권1호
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• pp.35-40
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• 1989

In order to study the follicular atretic mechanism in mammalian ovary, the relationship between pyknotic index (PI) of granulosa cells and the steroid concentrations in the follicular fluid of atretic follicle was investigated. Follicles were isolated from porcine ovary according to their sizes and the reproductive phases. Steroid concentrations were quantified by high-performance liquid chromatography. As PI increased, the concentration of progesterone was significantly increased(p<0.05), whereas testosterone and estradiol showed no significant changes in their concentration. As follicular size was increased, PI of follicular GC in the luteal phase was increased significantly(p<0.05) and the molar ratio of progesterone to testosterone was increased in the follicles of follicular phase. It can be concluded that progesterone accumulated in the follicular fluid as atresia of the follicles was progressed, and that PI of granulosa cells could be used as one of convenient and pratical criteria for the identification of follicular atresia.

• Clinical and Experimental Reproductive Medicine
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• 제13권1호
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• pp.29-38
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• 1986

In order to study the mechanism of follicular atresia, follicles were classified into the normal groups and the atretic ones, according to the criteria with or without corpus luteum, size of follicles, vascularization, status of granulose cells and the hypertrophy of theca layers in the porcine ovary. To estimate the binding capacity of human chorionic gonadotropin (hCG) receptor on the granulosa cells during atresia, hCG were iodinated by the chloramine-T method and then purified through the column chromatography. The concentration" of hCG receptor in each group were measured by the hCG receptor binding assay. Binding capacity in large normal follicles were 1.16%, but atretic ones were 0.45%. But in medium and small follicles (below 6mm in diameter), the binding capacity in normal follicles were 0.09%, but atretic ones were 0.05%, which was lower than those of large follicles. The present ( ) that the concentrations of hCG receptors on granulosa cells is decreased when the follicles become atretic and be used as a sort of creteria for the identification of follicles atresia.

• Journal of Animal Science and Technology
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• 제46권4호
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• pp.571-584
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• 2004

난포폐쇄는 과립층세포와 난포막세포들의 아포토시스에 의해 이루어지고, 이 과정에 대식 세포는 아포토시스 소체들의 포식작용과 각종 사이토카인 분비를 통해 난포폐쇄의 개시와 완성에 직, 간접적으로 관여함이 널이 보고되어 있다. 그러나 난포 폐쇄시 일어나는 아포노시스가 어디에서부터 개시되고, 어떻게 파급되는지, 아포토시스 소체의 제거방법, 퇴화된 난모세포의 제거 방법, 이들을 제거하는 대식세포의 난포내 진입 시기와 방법 등에 대해서는 아직 확실히 밝혀져 있지 않다. 이에 저자들은 가임기 돼지(Yorkshire-breed)를 실험동물로 난소내 난포의 광학현미경적 및 투과전자현미경적 관찰과 TUNEL 및 돼지 대식세포 단크론항체 4E9를 이용한 면역조직화학적 방법으로 본 연구를 실시하였다. 본 연구 결과, 난포 폐쇄는 과립층세포의 아포토시스로부터 개시되고 그 시기에 난포막 속층 세포들의 아포토시스도 같이 일어나는 것으로 관찰되었다. 과립층세포의 아포토시스는 당해 세포의 과립층내 위치에 관계없이 핵농축으로부터 시작되고 짧은 시간안에 과립층 전체로 파급되고 난모세포를 둘러싸고 있는 괴립층세포의 아포토시스가 가장 마지막에 일어나는 것으로 보인다. 난포 과립층세포의 아포토시스는 핵의 농축과 변형, 세포내 소포들의 출현이 특징적이었고, 아포토시스 소체들은 인접한 정상적인 과립층세포와 대식세포들에 의해 포식되었다. 아포토시스 소체들을 포식한 정상 괴립층세포는 자신도 곧 아포토시스를 일으켜, 이들의 포식작용은 일시적인 것으로 생각된다. 또한 모든 아포토시스 소체들과 퇴화된 난모세포는 대식 세포들이 제거함을 알 수 있었다. 대식세포는 아포토시스의 개시와 함께 난포내로 진입하고, 그 진행과 함께 난포내 모든 부위로 이동하여 아포토시스 소체들과 퇴화 난모세포를 제거하는 것으로 보인다. 처음부터 난포막에 있던 일부 대식세포들은, 아포토시스를 일으켜 난포 바닥막을 와해시킨 난포막세포들의 아포토시스 소체들을 제거하여, 폐쇄된 난포의 난소 실질화를 통해 난포 폐쇄의 완성에 기여하는 것으로 보인다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1994년도 한국생물과학협회 학술발표대회
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• pp.161.2-161
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• 1994

No Abstract, See Full Text

• 대한생식의학회:학술대회논문집
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• 대한불임학회 1997년도 춘계 학술대회
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• pp.14-15
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• 1997