• Korean Journal of Animal Reproduction
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• v.15 no.1
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• pp.59-66
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• 1991

This study was carried out to investigate the length of the estrous cycle and duration of estrus in Korean native goats. The effects of the type of last estrus : induced or natural, and the length of preceeding estrous cycle on the subsequent cycle and duration of estrus in goats were also examined. From 481 observations, the mean length of estrous cycles was 18.1${\pm}$0.5days. The cycle length was significantly(P<0.05) shorter following induced estrus (15.2${\pm}$0.8 d) than natural estrus(19.0${\pm}$0.6 d). Significantly higher(P<0.05) incidence of short estrous cycle was observed following induced estrus(40%) than natural estrus(27%). The frequency distribution in the estrous cycle was 30%, 3%, 56% and 11% for short(3-11 d), medium(12-16 d), normal(17-24 d) and long(${\geqq}$25 d), respectively. The most frequent type of short estrous cycle was 6 days in length. Mean duration of estrus was 34.0${\pm}$0.5 h with a range of 18 to 84 h. Duration of estrus was not significantly different the preceeding natural (33.8${\pm}$0.6 h) and induced estrus (34.4${\pm}$1.1 h), and was not significantly affected by the last cycle length. These results suggest that the short estrus cycles are more frequent following induced estrus than natural one, and the duration of estrus are affected greatly by the various intrinsic and extrinsic factors.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.70-70
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• 2003

The uterus undergoes dynamic changes during the cycle and displays many features typical of developmental process. In order to be prepared for implantation, endometrium undergoes predictable, sequential phases of proliferation and secretory changes. The uterus during estrus cycle synthesize a complex of signaling molecules with specific spatial and temporal modes of expression and which are critical for cell proliferation and differentiation. The purpose of this investigation was to use cDNA microarrays to evaluate the expression of genes of rat uterus in estrus cycle. Animals were sacrificed on proestrus, estrus, metestrus, diestrus. Differential gene expression profiles were revealed(growth-related c-myc reponsive protein RCL, heat shock 47-kDa protein (HSP47), cytochrome c oxidase polypeptide Vlc2 (COX6C2), calreticulin (CALR)). Reverse transcription polymerase chain reaction (RT-PCR) was used to validate the relative expression pattern. Using this approach, we found several genes whose expression in rat uterus was altered with estrus cycle. Our long-term goal is to determine the role of these differentially expressed genes during estrus cycle. This study was supported by through the Biohealth Products Research Center(BPRC), Inje University.

• Journal of Embryo Transfer
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• v.4 no.1
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• pp.41-45
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• 1989

Total thirty of flushing were attempted on day 4 to 15 of estrus cycle with S heifers and 9 cows by nonsurgical method. The flushed or recovered rate among flushings was 86.7% (26/30) or 88.5% (23/26), respectively. There was no difference in the recovered rate between heifers (85.7%,6/7) and cows (89.5%, 17119). The embryo was recovered on day 4 to 15 of estrus cycle from the donors in natural heat without any technical difficulties.The I2FG Foley catheter used for pubertal heifers had sometimes plug in it with uterine mucus during flushing of uterine horn. But the problem could be overcomed by pumping the catherter with fluthing solution or by changing the catheter. Three normal embryos were recovered from 3 pubertal (10-11 month old) heifers. The rate of normal and abnormal eggs was 60.9% (14123) and 39.1% (9/23), respectively. The abnormal eggs were on degenerating except one unfertilized egg and were mostly recovered from heifers or cows flushed consecutively during the estrus cycle. The developmental states of normal embryos were l6-cells on day 5, 32-cells on day 6, compacted-morula on day 7, early-to expanded-blastocyst on day 8-to 9, and hatching-to hatched-blastocyst on day 10 to 11 of estrus cycle. The stage of embryos on day 8 to 10 showed varities among donors. On day 8 to 9 of estrus cycle hatching-blas tocyst was recovered from some donors.

• Korean Journal of Animal Reproduction
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• v.14 no.3
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• pp.175-182
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• 1990

Behavioural estrus and short estrous cycles were observed and serum concentrations of estradiol-17$\beta$(E2) before and after of estrous were measured following superovulation treatments in 30 pluriparous Korean native goats. The goats were divided into 2 groups. Fifteen goats were injected IM with 1,000IU PMSG on Day 12 of the estrous cycle followed by 10mg PGF2$\alpha$ 48h later(P4＋PMSG), and the other 15 goats were injected IM with 10mg progesterone(P4)in oil once daily for 10d beginning at any days of estrous cycle followed by 1,000IU PMSG and 10mg PGF2$\alpha$ at the 8th day of progesterone treatment(P4＋PMSG group). After injection of PGF2$\alpha$, onset of standing estrus occurred in 12 of 15 goats(80.0%) at 50.0$\pm$7.7h and in 11 of 15 goats(73.3%) at 135.6$\pm$10.1h in PMSG and group and P4＋PMSG group, respectively. The mean interval from PGF2$\alpha$ injection to first estrus was significantly(P<0.01) earlier in PMSG group than in P4＋PMSG group. This result indicate that the delayed infusion of P4 in P4＋PMSG group caused the later exhibition of their estrous behaviors. However, duration fo frist estrus(31.5$\pm$2.6h vs 26.2$\pm$2.3h), length of estrous cycle(14.1$\pm$3.3d vs 16.6$\pm$3.8d) and percentage of short estrous cycle(50.0% vs 45.5%) were not different between PMSG and P4＋PMSG group. The mean concentration of serum E2 in 4 goats showing normal estrous cycle in P4＋PMSG group(PP-NEC) was higher than in 6 goats showing normal(P-NEC) or in 6 goats showing short estrous cycle(P-SEC) in PMSG group. The peak level of serum E2 was observed at the time of onset of standing estrus in PP-NEC(67.6pg/ml), 6h earlier in P-NEC(53.1pg/ml) and 6h later in P-SEC(52.3pg/ml) than the onset of standing estrus. The profiles of serum concentration of E2 during the period of peri-estrus was similar in the goats of PMSG or P4＋PMSG and also in the goats showing the subsequent estrous cycle of normal or short length.

• Korean Journal of Veterinary Research
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• v.21 no.2
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• pp.167-170
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• 1981

Changes in serum glutamic oxaloacetic transaminase (s-GOT) activities, serum alkaline phosphatase activities and serum total protein amounts were investigated on seven Korean native cows having normal estrus cycle of 18~24 days after normal parturition, dividing estrus cycle into estrus (0~1 days), metestrus (2~6 days), diestrus (7~16 days), proestrus (17~20 days). The results were as follows. 1. Serum GOT activities at estrus ranged from 73.5 to 121.5 Ku with a mean of $89.14{\pm}17.16$ Ku, at metestrus 57 to 89 Ku with a mean of $67.01{\pm}10.81$ Ku, at diestrus 54 to 89.5 Ku with a mean of $67.05{\pm}10.05$ Ku and at proestrus 53 to 112 Ku with a mean of $73.00{\pm}20.05$ Ku. The activities were significantly increased at the estrus comparing with other stages (P<0.01). 2. Serum ALP activities at estrus ranged from 8.0 to 10.4 K-Au with a mean of $8.74{\pm}0.83$ K-Au, at metestrus 6.5 to 9.2 K-Au with a mean of$7.74{\pm}0.76$ K-Au, at diestrus 5.6 to 9.0 K-Au with a mean of $7.67{\pm}1.13$ K-Au, at proestrus 6.2 to 9.3 K-Au with a mean of $7.12{\pm}1.18$ K-Au. The significance was not recognized among the stages of estrus cycle. 3. Serum total protein amounts at estrus ranged from 6.45 to 8.0g/10dl with a mean of $7.25{\pm}0.57/100dl$, at metestrus, 6.37 to 7.9g/100dl with a mean of $7.65{\pm}0.50g/100dl$, fat diestrus, 6.56 to 8.67g/100dl, with a mean of $7.53{\pm}0.55g/100dl$ and at proestrus 5.94 to 7.71g/100dl with a mean of $6.54{\pm}0.65g/dl$. There was not significance among the stages of estrus cycle.

• Clinical and Experimental Reproductive Medicine
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• v.47 no.1
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• pp.12-19
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• 2020

Objective: The appropriate function of the hypothalamic-pituitary-gonadal axis is essential for maintaining proper reproductive function. In female mammals, the hypothalamic-pituitary-gonadal axis regulates reproductive changes that take place in the estrus cycle and are necessary for successful reproduction. This study was conducted to investigate the effect of thymectomy on the estrus cycle in neonatally thymectomized guinea pigs. Methods: In this study, 12 female guinea pigs, six thymectomized and six sham-operated, were studied. The effects of neonatal thymectomy at 5-7 days of age on parameters of the reproductive axis were examined in female guinea pigs. Gonadotropin and 17β-estradiol levels were assessed at regular intervals (days 0, 3, 6, 9, 12, and 15) of the estrus cycle, and the time of vaginal opening in the thymectomized and shamoperated guinea pigs was determined. Results: Significant reductions in gonadotropins and 17β-estradiol levels during estrus cycle were found in neonatally thymectomized female guinea pigs compared to sham-operated guinea pigs. Conclusion: The results of this study underscore the importance of the thymus in the neonatal period for normal female reproductive function.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.35-41
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• 2008

This study was undertaken to investigate the distribution of major histocompatibility complex class II positive (MHC II+) (HLA-DP-like) cells in the cow uterus (cervix, corpus and cornu uteri) and to compare these cells between the estrus and diestrus phases of the estrous cycle. Twenty-nine multiparous cows were used. Tissue samples from the middle of the cervix, the corpus and the right cornu were taken immediately after slaughter at the estrus or diestrus phase. Streptavidin-biotin peroxidase complex staining was used to detect MHC II+ cells. The number of MHC II+ cells per unit area of tissue was counted using image analysis software under a light microscope. Numerous MHC II+ cells were found in the endometrium (cervix, corpus and cornu uteri) in both estrus and diestrus. MHC II+ cells were found in the surface epithelium of the cervix uteri in diestrus, but in the corpus uteri in both estrus and diestrus and in the cornu uteri in estrus. MHC II+ cells were also found freely in the lumen of the glands and between the gland epithelia of the corpus and cornu uteri in both estrus and diestrus. There were also MHC II+ cells in the connective tissue of the myometrium and perimetrium (outside the endometrium) and around the blood vessels. Endothelial cells were frequently positive for MHC II staining. More MHC II+ cells were found in the endometrium than outside the endometrium in both estrus and diestrus (p<0.001). However, there was no difference in the numbers of positive cells between estrus and diestrus either in the endometrium or outside it. These results are the first evidence for HLA-DP-like MHC II+ cells in the bovine uterus. They indicate that antigen presentation by HLA-DP-like MHC II+ cells of the uterus is not influenced by hormonal status.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.384-388
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• 2003

To establish the method of estrus induction using the injection of PGF$_2$$\alpha$ㆍ the 60 dairy cows treated by PGF$_2$$\alpha$ㆍ at 6, 8, 10, 12, 14, and 16 day of estrous cycle, recpectively. The plasma progesterone concentrations at day of injection of PGF$_2$$\alpha$ㆍ were $1.5\pm$1.3 (mean$\pm$SD) ng/ml at 6 days of estrous cycle, 3.7$\pm$1.4 ng/ml at 8 days, 6.5$\pm$1.8 ng/ml at 10 days, 7.9$\pm$2.0 ng/ml at 12 days, 6.5$\pm$2.5 ng/ml at 14 days, and 2.5$\pm$1.2 ng/m] at 16 days, respectively. The percentages of induction of estrus after PGF$_2$$\alpha$ㆍ treatment were 52.8% at 3th day after treatment, 21.7% at 4th day, 8.3% within 2th day, and ] 7.2% after 5th day, respectively. The percentages of cows conceived at first service after induction of estrus were 73.3% on 16 days of estrous cycle at treatment, 66.7% on 10 and 14 days, 63.3% on 8 and 12 days, and 53.3% on 6 day, respectively. The percentages of cows conceived on first service were 70.5% at 3th day after induction, 66.7% at 4th day and 65% at 5th day, respectively. These results suggest that the PGF$_2$$\alpha$ㆍ treatment at regressing stage of corpus luteum showed high induction of estrus and pregnancy rate, and there were high induction of estrus and pregnancy rate at 3th and 4th day after PGF$_2$$\alpha$ㆍ treatment.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.455-462
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• 1999

This study was designed to investigate the number of the growing and mature follicles in each stage of estrus cycle in mature rats. Eighteen mature rats(Sprague-Dawley, initially 190~230gm) were randomly alloted into 4 groups(proestrus, estrus, metestrus, and diestrus) according to estrus cycles. The uteri and ovaries of rats were collected and then alternative sections of paraffin embedding ovaries were stained with H-E. Numbers of large, middle and small follicles or only large and middle follicles from secondary and tertiary follicles were investigated by LM photography of preparations. Small follicles were defined as secondary follicles with 2~5 cell layers of granulosa cells surrounding the oocyte, and middle follicles were defined as secondary follicles with more than 5 cell layers or with early signs of antral cavity or with more than one small cleft on either side of the oocytes and large follicles were defined as tertiary follicles with a single medium or large antral cavity. The number of follicles in a pair ovary per rat was appeared to be ranged from 207 to 370 and the mean number of these follicles was $270.4{\pm}52.6$ and the mean number of follicles per ovary was $134.9{\pm}32.0$. The mean number of large, middle and small follicles per ovary was appeared to be $16.4{\pm}4.4$($12.2{\pm}3.3%$), $36.2{\pm}8.6$($26.8{\pm}6.4%$), and $82.7{\pm}24.0$($61.3{\pm}17.8%$), respectively. The mean number of large and middle follicles in each stage group of estrus cycle was appeared to be $17.8{\pm}2.1$ and $38.3{\pm}7.4$ at proestrus stage group, $15.7{\pm}5.2$ and $38.0{\pm}10.0$ at estrus stage group, $16.5{\pm}3.5$ and $33.8{\pm}7.0$ at metestrus stage group, $16.7{\pm}5.8$ and $29.7{\pm}5.5$ at diestrus group, respectively. In histological findings of large follicles during each estrus cycle, the large follicles in proestrus group contain single small antrum, thick granulosa cell layers, and were $300{\sim}500{\mu}m$ in diameter and were growing follicles with PCNA-positive cells in the granulosa cell layers, and other luteinizing follicles of proestrus cycle stage were decreased in size and were thicker in wall thickness and more luteinized than those in metestrus and diestrus stage groups. The large follicles in estrus stage group contain thick granulosa cell layers and nonprominent cumulus-oocyte complexes in antrum, and were $400{\sim}700{\mu}m$ in diameter and were growing follicles with PCNA-positive cells in the granulosa cell layers. The large follicles in metestrus and diestrus stage groups contain enlarged antrums, thinner layers of walls and prominent cumulus-oocyte complexes, and were $700-950{\mu}m$ in diameter, and were nongrowing follicles without PCNA-positive cells or another large follicles contain cells with dark stainability and distinct boundary.

• Korean Journal of Animal Reproduction
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• v.14 no.4
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• pp.289-296
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• 1990

This experiment was carried out to investigate the recovery period of estrus cycle, the pseudopregnancy period, weights of ovary, placenta and fetus, and number of litter of female rats after unilateral ovariectomy(ULO). The results obtained are as follows : 1. The estrus cycle was inclined to become normal from the second time. 2. The pseudopregnancy period of rats in unilaterally ovariectomized group and control group, and no significant difference in pseudopregnancy period was shown between the two groups. 3. The ovarian weights of each ULO group were significantly(P<0.01) heavier than that of the control group throughout the observation periods of pregnancy. 4. The placental weights of ULO group were not different from that of the control group in 10 and 15 days of pregnancy. But they became significantly (P<0.05) heavier in 20 days. 5. The weights of fetus in ULO at 10 days of pregnancy was not different from that ofthe control group, but the weights in ULO group at 15 and 20 days of pregnancy were significantly(P<0.01) heavier. 6. The number of litter in ULO was smaller than that of the control groups.