• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.636-642
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• 2009

The corpus luteum (CL) is a transient endocrine gland that produces progesterone, a product required for the establishment and maintenance of pregnancy. In the absence of pregnancy, the production of progesterone in the CL decreases and the structure itself regresses in size. The life span and function of the CL are regulated by complex interactions between stimulatory (luteotrophic) and inhibitory (luteolytic) mediators. When an ovum is released from a mature follicle, angiogenesis and rapid growth of follicular cells form the CL. The purpose of the present study was to determine whether steroidogenesis, proliferation, and hypoxiarelated proteins are expressed in caprine CL. The expression of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor $1{\alpha}$ (HIF-$1{\alpha}$) were determined in caprine CL during the estrous cycle. Cytochrome P450 side chain cleavage protein did not vary significantly during the estrous cycle; however, there was an increased expression of $3{\beta}$ -hydroxysteroid dehydrogenase in the early and middle stages, which rapidly decreased in the late stage. The same observations were made with respect to steroidogenic acute regulatory protein. Variations in progesterone content and expression of PCNA, HIF-$1{\alpha}$, and VEGF were consistent with this result. Thus, the steroidogenic proteins, PCNA, HIF-$1{\alpha}$, and VEGF in caprine CL are dependent on the stage of the estrous cycle.

• Korean Journal of Animal Reproduction
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• v.17 no.3
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• pp.209-220
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• 1993

This study was attempted to investigate the processes of regression of the corpus luteum and uterus after parturition in 2∼3 multiparous Korean native goats. The concentrations of LH, prolactin and progesterone in blood plasma of native goats were measured at 5 day intervals from 10 days prepartum to 35 days postpartum. The pregnancy corpus luteum from goats at Days(D) 1, 10, 20 and 30 days of postpartum were examined by light microscopy. Changes in the uterus fo goats were studies by macroscopic and light microscopic observations during the postpartum period. Mean concentrations of plasma LH were low after parturition and the levels of plasma LH were similar during late gestation and throughout the postpartum period. Mean plasma concentrations of prolactin were 0.30 0.06 and 0.38 0.13ng/ml at Day 5 and Day 10 prepartum, respectively, but PRL levels remained slightly high for 5 weeks after kidding. Mean levels of progesterone in plasma were 0.33 0.05ng/ml on Day 1 postpartum(P<0.01). Through light microscopic survey, pregnancy corpora lutea were quite degeneration by day 10 pospartum. Microscopic changes of CL regression consisted of cytoplasmic eosinophilia and vacuolation, and pyknosis and karyorrhexis of the nucleus of luteal cells. Vascular changes were distended at the periphery ofthe CL. From macroscopic measurements of the uterus, the uteri were returned to their initial non-pregnant stage within a period of 21 dyas after parturition. Following partuition the intercaruncular epithelium was reparied by 20 days. The uterine epithelium was partially recovered in the carucle by 30 days postpartum.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.457-461
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• 2018

Corpus luteum (CL) is a transient endocrinal tissue that undergoes repeated formation and regression during the estrous cycle. In this study, we hypothesized that the functional and structural mechanism of angiogenesis is similar between CL and tumor formation. First, we measured mRNA and protein expression of angiogenic receptors (vascular endothelial growth factor receptor-2, VEGFR2; Tie 2) in the early, middle, and late phase CL tissues during the estrous cycle. Ral-interacting protein of 76 kDa (RLIP76) and H-ras mRNA and protein were also expressed in the CL tissues. VEGFR2 and Tie 2 mRNA and protein were expressed in the early and middle phase CLs and decreased in the late phase. H-ras mRNA and protein were expressed in the early and middle phase CLs, but not in the late phase. RLIP76 mRNA was expressed in all phase CLs, and the protein expression was highest in early phase CLs. We suggest that RLIP76 and H-ras, an oncogenic gene, regulate the function of the CL during the estrous cycle, and the proteins will play an important role in the angiogenic mechanism of the CL.

• Development and Reproduction
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• v.26 no.2
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• pp.71-77
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• 2022

In response to luteinizing hormone (LH), a higher concentration of progesterone (P4) is produced in luteal cells of corpus luteum (CL). Mitochondria are an essential cellular organelle in steroidogenesis. The specific engagement of the concept regarding mitochondrial shaping with early stages of steroidogenesis was suggested in reproductive endocrine cells. Although the specific involvement of GTPase dynamin-related protein 1 (Drp1) with steroidogenesis has been demonstrated in luteal cells of bovine CL in vitro, its actual relationship with ovarian steroidogenesis during the estrous cycle remains unknown. In this study, while Fis1 and Opa1 protein levels did not show significant changes during the estrous cycle, Drp1, Mfn1, and Mfn2 proteins exhibited relatively lower levels at proestrus than at estrus or diestrus. 3β-HSD showed higher levels at proestrus than at estrus or diestrus. In addition, Drp1 phosphorylation (s637) was higher in proestrus than in estrus or diestrus. Immune-positive cells for Drp1, pDrp1 (s637), and 3β-HSD were all localized in the cytoplasm of luteal cells in the CL. The immune-positive cells for 3β-HSD were more frequently seen in the CL at proestrus than at estrus or diestrus. Immunoreactivity for Drp1 in luteal cells at proestrus was weaker than that at estrus or diestrus. However, pDrp1 (s637) immune-positive cells were mostly detected in luteal cells at proestrus. These results imply that steroidogenesis (P4 production) in the CL is closely related to phosphorylation of Drp1 at serine 637. Taken together, this study presents evidence that Drp1 phosphorylation at serine 637 is an important step in steroidogenesis in the CL.

• Korean Journal of Animal Reproduction
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• v.25 no.1
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• pp.9-17
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• 2001

To determine the effect of the characteristics of the corpus luteum (CL) and serum metabolites on pregnancy rate following embryo transfer in Hanwoo cow, recipients were synchronized the estrus with CIDR. in vivo or in vitro produced bovine embryos were transferred to synchronized recipients. The characteristics of the CL were checked by rectal palpation and ultrasound. Blood samples were collected from jugular vein at Day 7 and analysed progesterone and serum metabolites. The results obtained from this study were as follows; 1. Total 397 embryos were transferred to recipient and 121 heads out of them were pregnant. The pregnancy rate was 30.5% and slightly differences between farms. 2. There was not significantly different the pregnancy rates between the size of CL and the cavity CL. In the recipients which had more than 2ng/$m\ell$ of serum progesterone level, the pregnancy rates was in higher than others (46.6% vs. 24.4%, 15.0%). 3. The highest pregnancy rate was obtained at 90 to 110mg/㎗ in serum total cholesterol, 14 to 16mg/㎗ in BUN, and 70 to 80mg/㎗ in serum glucose, respectively, and these metabolites in blood could be used as the criteria in the selection of recipient at embryo transfer.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.133-139
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• 2012

This study was carried out to develop the useful inducing method of estrus for Korean native cows. Under the condition of estrus induction by administering $PGF_{2{\alpha}}$ for the cows in which corpus luteum (CL) in ovaries was detected by ultrasonography, ovarian responses and the changes of progesterone ($P_4$) concentration against $PGF_{2{\alpha}}$ compared with conception rate were observed in cows and heifers. In inducing estrus administering $PGF_{2{\alpha}}$. to the cows which has corpus luteum in ovaries, ovarian reponses, the changes of progesterone concentration, and conception rate were identified and compared. The results attained from the studies were as follows. Significant decreases of CL in size over time after $PGF_{2{\alpha}}$ administration were detected in both cow and heifer groups (p<0.001), but not different between groups in the CL regression rate (p>0.05). In addition, the percentage changes relative to the plasma $P_4$ concentration on day 1 after $PGF_{2{\alpha}}$ treatment were decreased to below 1ng/ml. The growth rate of follicle was observed as 31% on day 1 and 42% on day 2 in cows, and 34% on day 1 and 97% on day 2 in heifers, resulting that growth of heifers are faster than that of cows (p<0.05). The conception rate after $PGF_{2{\alpha}}$ treatment were 60.5% and 64.2% in cows and heifers, respectively. It also indicated that the conception rate after estrus observation with $PGF_{2{\alpha}}$ injection was as high as 66.6% while that with timed-artificial insemination (TAI) regardless of the estrus observation was 56%, which means the pregnancy rate of artificial insemination after estrus observation was higher than that of TAI (p<0.05). In the result of all above, there were significant decreases in CL size and the plasma $P_4$ concentration by days but rapid growth in follicles, which has no differences in cows and heifers. The conception rate was commonly high after estrus observation and more than 50% under TAI.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.263-270
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• 2000

The ovaries of 178 Holstein heifers or cows (heifer; 41, 1 parity; 72, 2$\leq$ parity; 65) on Day 6 or 7 (Day 0=day of estrus) were examined by transrectal ultrasonography. Diameter of corpus luteum (CL) and large follicle ( $\geq$ 10 mm), and luteal tissue area were determined by ultrasound system with a 5 MHB rectal probe. Blood samples were taken to progesterone analysis. After selection of recipients, frozen Holstein embryos were thawed and directly transferred to recipients non-surgically. The diameter of CL and luteal tissue area was greater (P<0.01) on Day 7 than on Day 6 in heifers, 1 parity or 2 $\leq$ parity cows, respectively, although progesterone concentrations were not different. The presence of fluid-filled luteal cavitied or multiple CL (2 or more) did not affect serum progesterone concentration. A large follicles were observed in 67.4% of heifers or cows and the average diameter was 14.1 mm. Greater luteal tissue area attributed higher pregnancy in heifers, but not in cows, although there were no difference on pregnancy rate according to progesterone concentration in heifers or cows. The pregnancy rate of recipients contained a large follicle at embryo transfer was lower than that of recipients not contained. These results show ultrasonic assessment of ovaries in Holstein recipients is a reliable tool to determine the follicle and CL for recipient selection.

• Journal of Life Science
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• v.22 no.5
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• pp.687-691
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• 2012

The present study evaluated the localization of luteinizing hormone receptors (LHR) and galectin-3 (Gal-3), a beta-galactoside-binding animal lectin, in the mature mouse ovaries by immunohistochemical analysis. Intense LHR immunoreactivity was detected in the active corpus luteum (CL), whereas expression of Gal-3 was high in the regressing CL and atretic follicle. In the CL of pregnant mice, LHR immunoreactivity was intense, but Gal-3 expression was low. Thus, LHR and Gal-3 had opposite patterns of expression in mature mouse ovaries, suggesting that both proteins have stage-specific expression patterns and are possibly involved in CL formation and regression.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.229-235
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• 2011

Sloan-Kettering virus gene product of a cellular protooncogene c-Ski is an unique nuclear pro-oncoprotein and belongs to the Ski/Sno proto-oncogene family. Ski plays multiple roles in a variety of cell types, it can induce both oncogenic transformation and terminal muscle differentiation when expressed at high levels. Ski protein is implicated in proliferation/differentiation in a variety of cells. The alternative fate of granulosa cells other than apoptosis is to differentiate to luteal cells, however, it is unknown whether Ski is expressed and has a role in granulosa cells undergoing luteinization. Thus, the aim of this study was, by means of immunohistochemical methods, to locate Ski protein in the rat ovaries during ovulation and corpora lutea (CL) formation to predict the possible involvement of Ski in luteinization. In addition, we performed to examine whether the initiation of luteinization with luteinizing hormone (LH) directly regulates expression of Ski in the luteinized granulosa and luteal cells after ovulation by in vivo models. In order to examine the expression pattern of Ski protein along with the progress of luteinization, follicular growth was induced by administration of equine chorionic gonadtropin to immature female rat, and luteinization was induced by human chorionic gonadtropin treatment to mimic luteinizing hormone (LH) surge. While no Ski-positive granulosa cells were present in preovulatory follicle, Ski protein expression was induced in response to LH surge, and was maintained after the formation of corpus luteum (CL). These results indicate that Ski is profoundly expressed in the luteinized granulosa cells and luteal cells of CL during luteinization, and suggest that Ski may play a role in luteinization of granulosa cells.

• Korean Journal of Veterinary Research
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• v.29 no.3
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• pp.361-371
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• 1989

This study was performed to investigate the effects of stage and quality of embryo, synchrony between donor and recipient and difficulty of transfer on pregnancy rate following non-surgical transfer of frozen-thawed bovine embryos. The results were as follows; 1. The overall pregnancy rate of this experiment was 63.4% and that of heifers(73.1%) was higher than that of cows(46.7%). 2. The pregnancy rates of recipients transferred with morulae, early blastocysts and blastocysts were 50.0%, 64.7% and 71. 4%, respectively. 3. The pregnancy rate of recipients transferred with good embryos(67.9%) was higher than that of recipients transferred with fair embryos(53.8%). 4. The pregnancy rates of embryos transferred to left and right uterine horn were 63.2% and 63.6%, respectively. 5. The pregnancy rate of recipients in estrous synchrony 0(76.2%) was higher than those of recipients in synchrony -1(55.6%) and +1(44.4%). 6. The pregnancy rate of recipients transferred with 2 embryos (71. 4%) was higher than that of recipients transferred with 1 embryo(61.8%). 7. The pregnancy rate of embryos transferred to uterine tip (72.0%) was higher than that of embryos transferred to uterine base(50.0%). 8. Ease of transfer was ranked to a scale of one to three on the basis of increasing difficulty. Transfers ranked as ease score 1 accounted for 77.8% of pregnancies and had higher pregnancy rate than ease score 2(66.7%) or 3(45.5%). 9. The pregnancy rate of recipients with excellent corpus luteum(CL) (70.0%) was higher than those of recipients with good CL(61.1%) or fair CL(61.5) %. In reviewing above results, it was considered that the factors such as embryo stage, embryo quality, estrous synchrony, corpus luteum quality, transfer site within uterus, recipient's parity and ease score affected the pregnancy rate after non-surgical transfer of frozen-thawed bovine embryos.