• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.79-79
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• 2001

This study was conducted to measure the total protein, DNA, and RNA contents of corpus luteum(CL) in various stages of estrous cycle and pregnancy. CLs were collected from a local slaughterhouse and stages of the estrous cycle of CL were classified as CL1~2, days 1 to 10; CL3(with/without central cavity), days 11 to 17; CL4, days 18 to 20 by method of Ireland et. al(1980) and stages of the pregnancy of CL were classified as P1~3, months 11~3: P4~6, months 4~6; P7~9, months 7~9 of pregnancy. CL3 with/without central cavity(CC) was identified as described by Kastelic et. al.(1990)-CL with CC, more than 2mm in diameter; CL without CC, less than 2mm in diameter. In total protein content, CL3 with CC was significantly lower than P7~9(p<.05). The total DNA content was lower in CL3 with CC than CL3 without CC and CL4(p<.05). In protein : DNA ratio, CL3 with CC was significantly lower than CL4(p<.05), CL3 without CC was significantly lower than P7~9(p<.05), CL4 was significantly lower than CL3 with CC, P1~3 and P7~9(p<.05). No differences were observed in RNA content, protein:RNA ratio, RNA/DNA of CLs in stages of estrous cycle and pregnancy.

• Korean Journal of Animal Reproduction
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• v.26 no.1
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• pp.73-78
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• 2002

This study was conducted to investigate total protein, DNA, and RNA content in corpus luteum(CL) without and with central cavity in dairy cow. Stage of the estrous cycle of corpus luteum from slaughterhouse(CL3, days 11 to 17) was classified by method of Ireland et. al.(1980). Corpus luteum was classified into corpus luteum without(less than 2mm in diameter) and with central cavity(more than 2mm in diameter) by method of Kastelic et. al.(1990). 1 In total protein content, CL with central cavity did not differ from CL without central cavity. 2. In DNA content, CL with central cavity was significantly lower than CL without central cavity(p＜0.05). 3. In protein: DNA ratios, CL with central cavity was significantly lower than CL without central cavity(p＜0.05). 4. But in RNA content, protein:RNA and RNA:DNA ratios, CL with central cavity did not differ from CL without central cavity.

• Development and Reproduction
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• v.19 no.4
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• pp.227-234
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• 2015

The objective of this study was to investigate the expression of bovine luteum expressed sequence tags (ESTs), vascular endothelial growth factor (VEGF), and tumor necrosis factor receptor 1 (TNFR1) and the presence of functional ESTs in the bovine corpus luteum (CL) during different stages of the estrus cycle. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a difference in the expression of ESTs during the CL stage. Concentration of ESTs in the CL tissue increased significantly from the mid-luteal stage and decreased thereafter. RT-PCR analysis showed higher levels of the EST genes in the CL of the mid-luteal stage than in other stages, and the same level of expression of VEGF. Immunohistochemistry analysis of the tissue from CL formation to regression showed low cytosol and aggregation of the nucleus. And activity caspase 3 (apoptosis detector) was most strongly detected in the CL1 stage of bovine. During the estrous cycle, the cytosol was magnified and differentiation of the nucleus was clearly manifested. The ESTs affected the CL, and the relationship between VEGF and TNFR1 played a pivotal role for CL development and activation, dependent on the stage of CL. These results suggest local production of ESTs, the presence of functional ESTs in the bovine CL, and that ESTs play a role in regulating the function of cell death in bovine CL.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.390-400
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• 2000

The corpus luteum (CL) is a temporary endocrine gland whose main function is to secrete progesterone to support pregnancy. On the other hand, the cyclic bovine CL has also been shown to be a site of prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) production. Although there is general agreement that endometrial $PGF_{2{\alpha}}$ is an essential luteolysin in cattle, luteal $PGF_{2{\alpha}}$ seems to play a luteotropic role as an autocrine and/or paracrine factor, especially for the development and maintenance of the CL. This supposition is based on evidence that some of the prerequisites for autocrine/paracrine mechanisms are present, including local production of $PGF_{2{\alpha}}$ and the existence of specific binding sites within the CL. The purpose of this paper is to review the regulation of luteal $PGF_{2{\alpha}}$ secretion, its action on CL as an autocrine and/or paracrine factor and the receptivity of bovine CL to. $PGF_{2{\alpha}}$.

• Biomedical Science Letters
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• v.25 no.1
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• pp.107-112
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• 2019

The corpus luteum (CL) is composed to various cells, such as luteal steroidogenic cells (LSCs), luteal thecal steroidogenic cells (LTCs), luteal endothelial cells (LECs), fibroblast, immune cells and blood cells. The life span of CL is controlled by proliferation and apoptosis of luteal cells. Therefore, this study investigated apoptotic factors in luteal cells derived from bovine CL. The CL tissues were collected from bovine ovaries and luteal cells were isolated from middle phase CL. Then, LTCs and LECs were separated according to cellular morphology from LSCs. The expression of Bax, Bcl-2, Fas and tumor necrosis factor 1 receptor (TNF1R) mRNA and protein were analyzed using quantitative RT-PCR and western blot. Results show that, Bax and TNFR1 mRNA expression were significantly increased at late group than early and middle groups, otherwise Bcl-2 were significantly decreased at late group than early group (P<0.05). Fas mRNA expression were significantly decreased in middle group compared to early and late groups (P<0.05). In addition, Bax and Bcl-2 mRNA in LTCs was lower than LSCs, Fas mRNA was higher than LSCs. The Bcl-2 protein expression was lower at LTCs than LSCs, especially Fas protein in LTCs was significantly lower than LSCs and LECs (P<0.05). Otherwise, TNFR1 protein of LTCs were similar with LSCs but higher compared with LECs. In conclusion, we suggest that the results may help understanding of apoptosis ability in luteal cells according to cell type during CL regression of estrous cycle.

• Journal of Embryo Transfer
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• v.26 no.1
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• pp.33-36
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• 2011

The objective of this work was to determine the effect of corpus luteum (CL) grade on pregnancy rate after embryo transfer in Korean cattle and we found that CL development was linked to pregnancy rate. The in vivo derived blastocyst-stage embryos were transferred to 15 recipients synchronized in the estrus cycles. Based on size and palpable characteristics, CLs were categorized into three grade. The grade three CL is not to be identified by rectal palpation. The pregnancy rates tended to increase with the increase in CL size of recipients. In grade one, two, and three, the pregnancy rates were 62.5%, 50.0%, and 0%, respectively. This result suggests that pregnancy rates after embryo transfer might be affected by the CL status of recipients.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.69-74
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• 2007

This study was performed to determine the estrous cycles by macroscopic observation of the ovarian changes using the laparoscopy and to make use of these results for embryo transfer in Korean black goat (Copra hircus aegagrus). Laparoscopic examinations of the ovaries were performed from 2 days after $CIDR^(R)$ removal to 22 days after ovulation. The serial morphological changes of follicles and corpus luteum (CL) were observed. CL was classified corpus hemorrhagicum(CH), corpus luteum (CL) and corpus albicans (CA) by its maturation and regression. On the day before ovulation (Day 0), Graafian follicles (GF) were found on one or both ovaries. On the day (Day 1) and $2^{nd}$day (Day 2) of ovulation, and ovulation depression (OD) and an early stage corpus hemorrhagicum $(CH_1)$ were observed at the site of GF, respectively. On Days 3 to 4, more developed and enlarged corpus hemorrhagicum $(CH_2\;and\;CH_3)$ arised from the ovulation of the GF with well vascularization. On Days 5 to 6, it was identified that mature corpus luteum $(CL_3)$ was grown on the ovary, and fully developed CL with adjacent follicles were occupied most part of the ovary on Days 17 and 18. Then the size of CL was diminished, and completely luteal regression $(CL_1\;or\;CA)$ with new large follicle was identified on Days 20 and 22. From these results, the 4 stages of the estrous cycle in Korean black goats were 1) estrus (Day 0) for 1 day, 2) metestrus $(Day\;1{\sim}4)$ for 4 days (stage of CH development), 3) diestrus $(Day\;5{\sim}16/17)$ for 12 or 13 days (luteal stage), and 4) proestrus $(Day\;17/18{\sim}20/22)$ for 4 or 5 days (stage of luteal regression and follicular growing). Laparoscopy for observation of ovarian changes was invasive than laparotomy. Additionally, it had advantages of reduced adhesion and quick operation time. It was considered that laparoscopic examination of ovarian changes will be useful for embryo transfer in the Korean black goats.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.307-322
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• 1996

The corpus luteum (CL) is formed by the action of a surge of luteinizing hormone (LH) on the pre-ovulatory follicle. Luteal cells derived from granulosa and theca interna cells continue to secrete progesterone for about two weeks. LH in domestic animals is essential for the normal secretion of progesterone at all stages of the luteal phase. For this process in the rodents, 20$\alpha$-hydroxysteroid dehydrogenase (20$\alpha$-HSD) is indispensable. 20$\alpha$-HSD is an enzyme to be a biologically inactive steroid. This enzyme plays a critical role in the regulation of the rat luteal function and reported to be present in steroid-producing tissues such as the testis and adrenal gland. We have purified 20$\alpha$-HSD and found two distinct 20$\alpha$-HSD molecules (HSD-1 and HSD-2). Their molecular weights are both estimated to be 33kd.The amino acid compositions of HSD-1 and HSD-2 are mostly similar, but there is a slight difference in the content of lysine. We demonstrated that 1) CL of previous generations contribute more to whole ovarian 20$\alpha$-HSD activity, 2) newly formed corpora lutea contain only 20$\alpha$-HSD-1 activity, and 3) old CL express activities of each HSD isozyme as shown in the luteal tissue of cycling rats on the day of diestrus where only degenerating old CL exist. The increase in 20$\alpha$-HSD activity identified seems to be related to the increase in the numbers of 20$\alpha$-HSD-positive cells. Interestingly, 20$\alpha$-HSD-1 activities were strongly found in the follicle fluids and theca interna cells by immunohistochemical study. Thus, the activity of 20$\alpha$-HSD may be related to a survival mechanism of those luteal cells and follicles remaining in the ovaries. Luteal cells arise from two sources. The small luteal cells are all of theca cell origin, while the large luteal cells are mainly of granulosa cell origin. CL of Korean Native Cattle, as those of other animal species, contains two morphologycally and functionally distinct luteal cell populations, such as small and large luteal cells as well as nonluteal cells. In all reproductive states except in the late luteal phase, the bovine CL also contained more small luteal cells than large luteal cells. Luteal tissue secretes a variety of growth factors (proteins) and the pattern of secretion changes during all stages of the luteal phase. These growth factors could be important in regulating the function of the bovine corpus luteum and may act in a potential endocrine autocrine and paracrine mechanisms. Therefore, further work has to be done to elucidate the role of growth factors in the ovary, especially in the corpus luterum. Interest should be focussed on interaction of these growth factors in the regulation of luteal cell and the localization of cytokine synthesis in differnet luteal cells.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1540-1545
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• 2012

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.711-720
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• 2005

In the corpus luteum, TNF$\alpha$ is known to induce functional and structural luteolysis. In addition, it acts as luteotropic agent during the initial and early stage of luteal development. In spite of its importance in corpus luteal development, there is still different opinions for the source cells of TNF$\alpha$ in the corpus luteum. One is the macrophages only, and the other is macrophages are the main source and endothelial cells are the minor source. In this experiment, using the porcine corpora lutea of pregnancy and ovulatory stages, hematoxylin-eosin stain, macrophage and TNF$\alpha$ immunohistochemistry were carried to reveal the sources of TNF$\alpha$. As a result, MAC 387-positive macrophages were present in all the stages of corpora lutea. In the mature corpora lutea of nonpregnant stages, the sites of MAC 387-positive macrophages and those of TNF$\alpha$- positive macrophages were coincided, and the sites of endothelial cells and those of TNF$\alpha$-positive endothelial cells were nearly coincided. But, in the mature CL of pregnant stage, mid- and advanced luteolytic stages of both nonpregnant and pregnant stages, the sites of MAC 387-positive macrophages and those of TNF$\alpha$-positive macrophages were coincided, but not in the endothelial cells. Accordingly, it can be concluded that macrophages are the main source of TNF$\alpha$ in the corpus luteum and endothelial cells are the minor source in the mature and mid-lytic stages, but, in the advanced luteolytic stage, macrophages are the only source of TNF$\alpha$.