• Journal of Embryo Transfer
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• v.5 no.1
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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.

• 대한생식의학회:학술대회논문집
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• 1999.11a
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• pp.51-52
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• 1999

• Reproductive and Developmental Biology
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• v.28 no.3
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• pp.147-153
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• 2004

The oocyte and its surrounding granulosa cells co-exist in a closed compartment called a follicle, although they receive many signals from other parts of the body. It is well established that the intercellular communications between the oocyte and granulosa cells are required for normal oocyte development and ovulation during folliculogenesis. Gap junctions are intercellular channels allowing the direct transmission of ions and small molecules between coupled cells. Several lines of studies have shown that multiple connexins (Cx, subunits of gap junction) are expressed in mammalian ovarian follicles. Among them, two major connexins Cx37 and Cx43 are expressed in different manner. While the gap junction channels formed by Cx37 are localized between the oocyte and encompassing granulosa cells, the intercellular channels by Cx43 are located between granulosa cells. In this review, I will summarize the general properties of gap junction channels and discuss their possible formation (or compatibility) of intercellular channels formed by the oocyte and granulosa cells.

• Development and Reproduction
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• v.1 no.1
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• pp.25-28
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• 1997

The present study was conducted to determine the effect of recombinant human follicle stimulating hormone (rhFSH) on the estrogen synthesis by human fetal ovarian tissues. Fetal ovaries were 18-19 weeks old (18 wks:n=1, 19 wks:n=2). One case of 19-week-old fetal ovaries were obtained from anencephalic fetus. Obtained ovarieswere cleaned and diced around $600\mu\textrm{m}$ pieces, and cultured in the sandwich agar bed system for 21-23 days. Estrone ($E_{1}$) and estradiol-17 $\beta$($E_{2}$) in the medium was measured by radioimmunoassay. Amount of $E_{2}$ synthesis was greater than $E_{1}$ in both normal cases. In contrast, fetal ovaries from anencephalic fetus did not produce neither $E_{1}$ nor $E_{2}$ in the presence or absence of rhFSH. Results suggest that the fetal ovaries have a capacity of estrogen production at 18-19 weeks of gestation Existence of FSH receptor is also supposed. Different results by anecephalic fetal ovaries suggest the difference in the development between normal and anencephalic fetal ovaries.

• Journal of Aquaculture
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• v.17 no.2
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• pp.128-132
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• 2004

Reproductive cycle of the brown sole, Limanda herzensteini was investigated by means of histological methods. The testis showed the presence of seminiferous tubule. The tubule consisted of many testicular cysts, each of which contained numerous germ cells - all at the same developmental stage. The ovary consisted of several ovarian lamellae and the oogonia originated from the inner surface of the ovarian lamella. Oocyte development was group-synchronous. Gonadosomatic index (GSI) of the male and female was the highest in January and March, respectively. Reproductive cycle could be classified into the growing (June-September), maturation (October-December), ripe and spent (January-March), and recovery and resting (April-May).

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.317-318
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• 2001

In crustacea the molting cycle is the most important physiological process affecting growth, behaviour, reproduction and population dynamics through their life span. Particularly molt cycle is closely related to reproductive cycle, and it is important to determine the successive stages of molt cycle to understand reproductive phenomena including ovarian cycle and the development of the embryos in the marsupium. (omitted)

• Development and Reproduction
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• v.13 no.2
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• pp.123-132
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• 2009

The gonadosomatic index (GSI), fatness, ovarian development, first sexual maturity, and fecundity of the Korean anchovy Coilia nasus were investigated by histological observations and morphometric analysis from January to December, 2007. The GSI and fatness began to increase in February, and reached the maximum in June when the ovary was getting mature and spawning occurred. Thereafter these parametes rapidly decreased in July when spawning occurred. Therefore, monthly changes in the GSI and fatness were closely related to ovarian maturation and spawning. The duration of ovarian development in females can be classified into five successive stages: early growing stage (February to March), late growing stage (March to April), mature stage (May to June), ripe and spent stage (June to July), and recovery and resting stage (December to January). Maturation and spawning of this species occurred between June and July during the period of high seawater temperature-long day length. Percentages of first sexual maturity in female individuals were over 50% for fish ranging 24.1 to 27.0 cm in total length, and 100% for fish over 30.1 cm in total length. The number of total eggs and mature eggs in the absolute fecundity were increased with the increase of total length and body weight, respectively. The number of total eggs and mature eggs in relative fecundity were also proportional to total length, but rather these numbers decreased in the maximum body weight (126.0${\sim}$150.0 g).

• Korean Journal of Clinical Laboratory Science
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• v.48 no.1
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• pp.8-14
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• 2016

Granulosa cells surround the oocyte within the ovarian follicle and play an essential role in creating conditions required for oocyte as well as follicular development. The current study was conducted to examine the gene expression profile of mouse ovaries during the primordial to primary follicle transition process. Total RNAs from mouse ovaries on day 5 and day 12 were synthesized cDNA using annealing control primers. The DEGs were cloned and their identities were analyzed by BLAST search. The Plekha5 and Anxa11 were highly expressed in primary follicle stage. By contrast, their expression was increased in granulosa cells at the primary follicle stage. We have successfully discovered a list of genes expressed in day 5 and day 12 ovaries and confirmed that some of them are differentially expressed in PMF and/or PRI. This is a spatial-temporal regulatory mechanism on the ovarian folliculogenesis through membrane fusion. The gene expression profile from the current study would provide insight for future study on the mechanism(s) involved in primordial-primary follicular transition. This will provide information for identification of the mechanism of ovarian dysfunction.

• Development and Reproduction
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• v.14 no.2
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• pp.83-89
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• 2010

Apoptosis is a crucial mechanism for the proper regulation of homeostasis. BCL-2 family proteins are key molecules which control cellular survival and apoptosis. MCL-1 (myeloid cell leukemia-1) is a pro-survival member of BCL-2 family that promotes the survival of cells, and is highly expressed in diverse cancers including ovarian cancer, leukemia, and cervical cancer. Previously we identified IEX-1 (immediate early response gene X-1) as a binding partner of MCL-1. In the present study, we demonstrated that overexpression of IEX-1 induced apoptosis of ovarian cancer cells. Moreover, IEX-1 significantly attenuated the pro-survival function of MCL-1 in these cells. Also, IEX-1-induced cell death activity was able to be modulated by changes in the expression level of MCL-1. Thus, these results suggest that both IEX-1 and MCL-1 modulate each other's function controlling cellular survival and death and the inhibitory activity of IEX-1 toward MCL-1 may be applied for the development of chemotherapeutics.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.3
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• pp.269-277
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• 2005

Objectives: Previously, we sought to compile a list of genes expressed during early folliculogenesis by using cDNA microarray to investigate follicular gene expression and changes during primordialprimary follicle transition and development of secondary follicles (Yoon et al., 2005). Among those genes, a group of genes related to the cell size growth was characterized during the ovarian development in the present study. Methods: We determined ovarian expression pattern of six genes related to the cell size growth (cyr61, emp1, fhl1, socs2, wig1 and wisp1) and extended into CCN family (${\underline{c}}onnective$ tissue growth factor/${\underline{c}}ysteine$-rich 61/${\underline{n}}ephroblastoma$-overexpressed), ctgf, nov, wisp2, wisp3, including cyr61 and wisp1 genes. Expression of mRNA and protein according to the ovarian developmental stage was evaluated by in situ hybridization, and/or semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and immunohistochemistry, respectively. Results: Among 6 genes related to the cell size growth, cyr61 and wisp1 mRNA was detected only in oocytes in the postnatal day5 mouse ovaries. cyr61 mRNA expression was limited to the nucleolus of oocytes, while wisp1 was expressed in the cytoplasm and nucleolus of oocytes, except nucleus. cyr61 mRNA expression, however, was found in granulosa cells from secondary follicles. The rest 4 genes in the cell size growth group were detected in oocytes, granulosa and theca cells. Cyr61 and Wisp1 proteins were expressed in the oocyte cytoplasm from primordial follicle stage. Especially, Cyr61 protein was detected in pre-granulosa cells, Wisp1 protein was not. By using RT-PCR, we evaluated and decided that Cyr61 protein is produced by their own mRNA in pre-granulosa cells that was not detected by in situ hybridization. cyr61 and wisp1 genes are happen to be the CCN family members. The other members of CCN family were also studied, but their expression was detected in oocytes, granulose and theca cells. Conclusions: We firstly characterized the ovarian expression of genes related to the cell size growth and CCN family according to the early folliculogenesis. Cyr61 protein expression in the pre-granulosa cells is profound in meaning. Further functional analysis for cyr61 in early folliculogenesis is under investigation.