• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1113-1116
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• 2009

The objective of this study was to compare the follicular population during spontaneous and $PGF_2{\alpha}$ induced oestrous cycles in Nili-Ravi buffaloes. In Exp.1, (n = 13 oestrous cycles) follicular population was monitored using ultrasonography on alternate days. Buffaloes were monitored for ovarian follicles from day 0 (first oestrus) until next oestrus. These animals were observed for oestrus twice daily using a teaser bull. Of 12 oestrous cycles, 9 (75%) had two waves of follicular activity and only 3 (25%) had three waves during the oestrous cycle. The mean number of small, medium and large follicles among various days of the oestrous cycle between two and three waves of follicular development were not significantly different (p>0.05). In Exp. 2, follicular population 3 days before oestrus was compared in buffaloes undergoing spontaneous (n = 12 oestrous cycles) and $PGF_2{\alpha}$ induced (n = 6) luteolysis. The mean number of small and large follicles increased (p<0.05) and the number of medium follicles decreased (p<0.05) during the 3 days before oestrus in buffaloes undergoing induced luteolysis as compared to those with spontaneous luteolysis. These results showed that the mean number of small, medium and large follicles among various days of the oestrous cycle were similar between the two and three waves of follicular development, and three days before oestrous the number of small, medium and large follicles altered due to induced luteolysis on day 9, compared to those with spontaneous luteolysis.

• Journal of Embryo Transfer
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• v.15 no.1
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• pp.77-83
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• 2000

The purpose of this study was to develop a breeding technique to increase Hanwoo of superior characteristics. In the present study, reproductive status of Hanwoo such as size of farm, breeding system and gestationi length was investigated. In addition, effect of low dose administration of prostaglandin F2$\alpha$(PGF2$\alpha$) on luteolysis was examined. The size of farm was classified by the total number of cows and the number of breeding stocks, respectively. The distribution of herd size of < 5, 6~10, 11~30, 31~50 and > heads was 31%, 15%, 39%, 4% and 11%, respectively. Furthermore, the distribution of breeding stock size of <5, 6~10, 11~30, 31~50 and > 50 heads was 36%, 28%, 31%, 3% and 3%, respectively. Average parity was 2.1 in breeding stock. In breeding pattern, artificial in semination(A.I), estrus synchronization-A.I and natural mating was 92.7%, 2.4% and 4.9% respectively. Gestational length of Hanwoo was ranged 253~316 days (average length : 285 days) after estrus( estrus=0). To induce luteolysis, PGF2$\alpha$ was injected into ovarian parenchyma by a modified ovarian injector. The effect of administration of 6mg PGF2$\alpha$ on luteolysis and estrus induction was betweer (P<0.01) when PGF2$\alpha$ was administered into ovarian parechyma than when administered intramuscluarly (71 vs. 91%). When PGF2$\alpha$ was injected into ovarian parenchyma, a decreased concentration to 3 mg did not significantly decreaed its luteolytic effect(92%). When AI was performed following PGF2$\alpha$ treatment, the intraovarian injection group yielded a higher pregnancy rate(69 vs. 88%) than the IM injection groups, regardless of the dosage. In conclusion these results suggest that increasing herd size and regular reproductive management are needed to improve reproductive efficiency in Hanwoo industry. Furthermore, intraovarian administration of PGF2$\alpha$ is effective way to induce luteolysis compared with intramuscular injection.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.191-202
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• 2006

In addition to the removal of dying or dead lutein cells by phagocytosis in many species, macrophages exert both luteotropic effect during maturation period and luteolytic effect during degenerative period via mediating autocrine/paracrine actions of self-producing cytokines in the corpus luteum. In this experiment, immunohistochemical and transmission electron microscopic (TEM) studies were performed to observe the morphologic changes of luteal macrophages during luteolysis. A small number of macrophages and low immunoreactivity were present at the mature stage. The number of macrophages and immunoreactivity gradually increased along the advance of luteolysis. Two subtypes of macrophages could be observed through TEM observation. One type of macrophage located between the large lutein cells contained no lipid droplets in their cytoplasm at mature stage. The other type of macrophage located near the blood vessels contained many lipid droplets in their cytoplasm during luteolysis. Particularly, no phagocytic macrophages were observed, which suggested the macrophages in the porcine corpus luteum did not involve in the phagocytotic elimination of dying lutein cells.

• Reproductive and Developmental Biology
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• v.39 no.1
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• pp.1-6
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• 2015

Luteolysis is a cyclical regression of the corpus luteum in many non-primate mammalian species. Prostaglandin $F_2{\alpha}$($PGF_2{\alpha}$) from the uterus and ovary induces functional and structural luteolysis in bovine. The action of $PGF_2{\alpha}$ is mediated by $PGF_2{\alpha}$ receptor located on the luteal steroidogenic and endothelial cell membranes. $PGF_2{\alpha}$ plays an important role in regulating nitric oxide production in endothelial cells of the bovine corpus luteum. Nitric oxide production and nitric oxide synthase activity are stimulated and induced by $PGF_2{\alpha}$ in luteal endothelial cells. Moreover, the reactive oxygen species inhibits progesterone secretion in bovine luteal cells and induces apoptosis. Thus, the interaction between $PGF_2{\alpha}$ and reactive oxygen species provides important aspects in physiology of the corpus luteum forfunctional and structural luteolysis.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.61-67
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• 2008

Objective: This study was attempted to look at the effect of dexamethasone on the luteolysis of corpus luteum in rats by immunohistochemical study. Methods: Counting with an optical microscope was conducted to make a comparison on difference in luteolysis and penetration of macrophage into three groups: control group of 30 female rats at 8 weeks of age, dexamethasone 0.1 mg administered group, and dexamethasone 1mg administered group. Results: As a result of TUNEL immunostaining, the percentage of luteolysis was significantly reduced in both dexamethasone 0.1 mg administered group and 1 mg administered group, and after ED1 immunostaining, macrophage invasion was reduced in dexamethasone 1 mg administered group. As a consequence of ED1 immunostaining, the immune response of macrophage was much decreased in dexamethasone 1 mg administered group than control group. Conclusion: Dexamethasone works on luteal cell, so it can suppress apoptosis. It can suppress luteolysis by suppression macrophage invasion into corpus luteum or suppress macrophage activation in corpus luteum.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.23-26
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• 2001

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.213-218
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• 2001

• Reproductive and Developmental Biology
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• v.37 no.3
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• pp.149-154
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• 2013

The aim of this study was to evaluate the changes of protein patterns in granulosa cells and corpus luteum in ovaries during the estrus cycle in cows. The estrus cycle was devided into five steps of follicular, ovulatory, early-luteal, mid-luteal and late-luteal phases. In results, 61 spots of total 85 spots were repeated on follicular phase and 51 spots of total 114 spots were repeated on ovulatory phase. The 40 spots of total 129 spots were repeated on early-luteal phase and 49 spots of total 104 spots were repeated on mid-luteal phase. Also 41 spots of total 60 spots were repeated on late-luteal phase. On the other hands, the 16 spots were indicated difference in follicular phase and ovulation phase had a difference 10 spots. It was showed difference No. 103 spot in ovulation phase, No. 135 spot in early-luteal phase and No. 175 and 176 spots in mid-luteal phase. Also, the 11 spots were expressed specifically in mid-luteal phase and No. 178 and 179 spots were difference of expression in late-luteal phase. We confirmed that there were 7 spots for ovulation, 4 spots for luteinization and 2 spots for luteolysis. Spot No. 89~93 in ovulation phase were transferrin, and spot No.94~98 were HSP60. Spot No. 103 was Dusty PK, spot No. 135 was OGDC-E2, and spot No. 175 and 176 were Rab GDI beta from luteinization. Spot No. 178 and 179 in luteolysis were vimentin. This results suggest that will be help to basic data about infertility.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.365-369
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• 1999

Interferon tau (IFN$\tau$), the pregnancy recognition signal in ruminants, suppresses transcription of the estrogen receptor (ER) gene in the endometrial luminal (LE) and superficial glandular epithelium (sGE) to prevent oxytocin receptor (OTR) expression and pulsatile release of luteolytic prostaglandin $F_{2{\alpha}}$ (PGF), Interferon regulatory factors one (IRF-l) and two (IRF-2) are transcription factors induced by IFN$\tau$ that activate and silence gene expression, respectively. Available results suggest that IFN$\tau$ acts directly on LE and sGE during pregnancy to induce sequentially IRF-l and then IRF-2 gene expression to silence transcription of ER and OTR genes, block the luteolytic mechanism to maintenance a functional corpus luteum (CL) and, signal maternal recognition of pregnancy. The theory for maternal recognition of pregnancy in pigs is that the uterine endometrium of cyclic gilts secretes PGF in an endocrine direction, toward the uterine vasculature for transport to the CL to exert its luteolytic effect. However, in pregnant pigs, estrogens secreted by the conceptuses are responsible, perhaps in concert with effects of prolactin and calcium, for exocrine secretion of PGF into the uterine lumen where it is sequestered to exert biological effects and / or be metabolized to prevent luteolysis.

• Biomedical Science Letters
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• v.19 no.3
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• pp.180-187
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• 2013

Hypoxia is an integral part of the environment during luteolysis. In this study we examined whether hypoxia could directly stimulate endothelial cells to produce nitric oxide (NO). Endothelial cells were cultured in hypoxic (5% $O_2$) or normoxic (20% $O_2$) conditions and the levels of total NO, inducible NO and endothelial NO was measured. We found that hypoxia but not normoxia upregulated NO production. The increased NO levels correlated with increased inducible NO synthase (iNOS) expression whereas expression of endothelial NOS (eNOS) expression remained constant. Addition of the iNOS specific inhibitor 1400W to hypoxic cultures prevented NO production suggesting that hypoxia-induced NO production in endothelial cells was due mainly to upregulation of iNOS. We also found that prostaglandin $F_{2{\alpha}}$ (PGF) production was unaffected by hypoxia suggesting that upregulation of NO was not due to increased synthesis of PGF. In summary, we report that endothelial cells cultured under hypoxic conditions produce NO via the iNOS pathway. This study provides the importance of the relation between the hypoxic environment and the induction of NO by endothelial cells during regression of the corpus luteum in the ovary.