• Journal of Embryo Transfer
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• v.21 no.3
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• pp.177-182
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• 2006

This study was conducted to investigate the effects of melengesterol acetate (MGA) and $PGF_{2{\alpha}}$ administrations on serum progesterone level, synchrony of estrus and conception rates in Han-woo. Firstly, ten heifers and one freematin were fed 0.5 mg MGA/day for 14 days in a grain carrier, and after 19 days of MGA feeding, a single injection of 25 mg $PGF_{2{\alpha}}$ were treated. Blood samples were collected to evaluate serum progesterone concentrations from the start of feeding of MGA until the end of feeding and subsequent estrous detection and artificial insemination (AI) at 3 days intervals, and on days of $PGF_{2{\alpha}}$ injection, estrous detection, AI, and 15th and 60th days after AI. The level of progesterone in the blood began to increase from 7 days after MGA feeding, and 9 days after feeding it became 5.4 ng/ml and maintained that level thereafter. On the 33th day when the $PGF_{2{\alpha}}$ was injected, it reached the peak level of 7.6 ng/ml. However, 2-3 days after $PGF_{2{\alpha}}$ injection, it dropped to 1.4 ng/ml drastically (p<0.05). Secondly, one hundred and ninety four Hanwoo heifers or cows were divided into two groups to compare estrous induction and conception rates: the one treated with MGA and $PGF_{2{\alpha}}$, (n=104) and the other with $PGF_{2{\alpha}}$ treatment (two injections at 11 days interval, n=90). The heifers or cows treated with MGA and $PGF_{2{\alpha}}$ were identical to those used as above. The percentages of heifers or cows showed estrus were higher in the $MGA+PGF_{2{\alpha}}$ treatment (91.3%) than in the $PGF_{2{\alpha}}$ treatment (72.2%, p<0.05). Conception rates were also higher in the $MGA+PGF_{2{\alpha}}$ treatment (94.2%) than in the $PGF_{2{\alpha}}$ treatment (88.9%, p<0.05). The results of this experiment indicate that estrus synchronization using $MGA+PGF_{2{\alpha}}$ is more effective than that using $PGF_{2{\alpha}}$ (two injections) in Hanwoo.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.27-32
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• 2007

This study was conducted to examine the effects of prostaglandin $F_2{\alpha}(PGF_2{\alpha})$ and prostaglandin $E_2 (PGE_2)$ on the expansion and hatching of bovine embryos. During the in vitro culture, embryos were cultured with the following groups: (1) 0, 1, 10 and 100ng/ml $PGF_2{\alpha}$ (2) 0, 1, 10 and 100 ng/ml $PGF_2{\alpha}$, (3) low concentration of $PGF_2{\alpha}$ ; low concentration of $PGF_2{\alpha}$, (1ng/ml : 1ng/ml), (4) low concentration of $PGF_2{\alpha}$ : high concentration of $PGF_2{\alpha}$ (1ng/ml : 10ng/ml) (5) high concentration of $PGF_2{\alpha}$ : low concentration of $PGE_2$ (10ng/ml 1ng/ml) (6) high concentration of $PGF_2{\alpha}$ : high concentration of $PGE_2$(10 ng/ml : 10ng/ml). In the results of this study, treatment of $PGF_2{\alpha}$ or $PGE_2$ did not affect in vitro development to blastocysts. However, the hatching rates of embryos cultured with 10ng/ml $PGE_2$(10.3%) and 1ng/ml $PGF_2{\alpha}$ 10ng/ml $PGE_2$(22.2%) were significantly (P<0.05) higher than in control (4.3% and 12.7%) and other treatment groups. All groups treated with high concentrations of $PGF_2{\alpha}$ showed decreased hatching rates. Thus, this results suggested that $PGF_2{\alpha}\;and\;PGE_2$ were concerned with the hatching in bovine embryos, and their effects on hatching were different by the concentrations.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.207-213
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• 2003

This objective of this experiment were to evaluate the effect of various estrus synchronization programs on estrus detection rate and pregnancy rate in Hanwoo. After Postpartum 60 Days, a total of 150 cows divided into 2 groups. Cows Group 1 were treated with one luteolytic dosage of PGF$_2$$\alpha$(25 mg, im; lutalyse. USA) on Day 0, and with a second dosage 14 d later; cows in Group 2 were treated with GnRH(l00 $\mu\textrm{g}$, im; Conceral. Korea) on Day 0, PGF$_2$$\alpha$ 7 d later, GnRH 2 d later, and then time-inseminated approximately 16 h after this second treatment with GnRH. Ovarian morphology was monitored cows by trans-rectal ultrasonography from 24 hr to 32 hrs after second GnRH injection. The result obtained summarized as follows: 1. Cows synchronization of estrus with GnRH+PGF$_2$$\alpha$+GnRH(Ov-synch) and PGF$_2$$\alpha$ were 91.3 and 40.0%, respectively. 2. Induced ovulation were 24 to 32hr after the second GnRH injection, but high induced ovulation was 28hr. 3. High conception rate were 24hr insemination after the second GnRH injection. 4. Conception rate with PGF$_2$$\alpha$, CIDR and GnRH treatment were 50.0, 36.0 and 76.9%, respectively.

• 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. $PGF_{2{\alpha}}$.

• 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.

• The Korean Journal of Physiology
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• v.17 no.2
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• pp.135-142
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• 1983

$PGE_2$ and $PGF_{2{\alpha}}$ are known to act similarly in a number of animal tissues. They both facilitate regression of corpus luteum(Poyser, 1972; Fuch et al, 1974; Coudert et at, 1974) and stimulate contraction of uterine muscle (Laudanski et al, 1977; Porter et al, 1979; Hollingsworth et al, 1980). It is, however, not known whether these two prostaglandins exert similar actions in osmotic fragility of erythrocytes (Rasmussen et al, 1975) and $PGF_{2{\alpha}}$ alters conformation of membrane proteins (Meyers aud Swislocki, 1974). The former effect may not be mediated through changes in c- AMP concentration in the cell, since the adenylate cyclase activity in human erythrocyte is extremely low (Rodan et al, 1976; Sutherland et al, 1962) and the latter effect implies that physical state (or fluidity) of the membrane is altered by $PGF_{2{\alpha}}$. The present study was undertaken to elucidate mechanisms of action of $PGE_2$ and $PGF_{2{\alpha}}$ on the human erythocyte membrane by examining their effects on osmotic fragility and $Ca^{++}$ binding to the membrane fragments. The results are summarized as follows: 1) $PGE_2$ and $PGF_{2{\alpha}}$ increased osmotic fragility at concentrations above $10^{11}\;M$, the effect being similar for both hormones. The concentration of NaCl for 100% hemolysis was $1/16{\sim}1/17\;M$ in the presence of $10^{11}\;M\;PGE_2$ or $PGF_{2{\alpha}}$ and 1/18 M in the absence of the hormone (control). 2) When erythrocytes were suspended in 1/15 M NaCl solution, $44.2{\pm}4.3%$ of cells were hemolyzed. Addition of $10^{12}\;M\;PGE_2$ or $PGF_{2{\alpha}}$ did not increase hemolysis. When the concentration of the hormones was increased to $10^{11}\;M$, however the degree of hemolysis increased markealy to about 80%. No further increase in hemolysis was observed at concentration of the hormones above $10^{11}\;M$. 3) The additional hemolysis due to $10^{11}\;M\;PGE_2$ and $PGF_{2{\alpha}}$ appeared to he identical regardless of absence or presence of $Ca^{++}\;(0.5{\sim}10\;mM)$ in the suspending medium. 4) In the absence of prostaglandin, the binding of $Ca^{++}$ to the erythrocyte membrane increased curvilinearly as the $Ca^{++}$ concentration increased up to 5 mM above which it leveled off. A similar dependence of $Ca^{++}$ binding on the $Ca^{++}$ concentration was observed in the presence of $10^{11}\;M\;PGE_2$ or $PGF_{2{\alpha}}$, however, the amount of $Ca^{++}$ bound at a given $Ca^{++}$ concentration was significantly higher than in the absence of the hormones. 5) As in the hemolysis, $PGE_2$ and $PGF_{2{\alpha}}$ did not affect the $Ca^{++}$ binding at a concentration of $10^{12}\;M$, but increased it by about 100% at concentration above $10^{11}\;M$. These result indicate that both tile osmotic fragility of erythrocyte and the $Ca^{++}$ binding to the erythrocyte membrane are similarly enhanced by $PGE_2$ and $PGF_{2{\alpha}}$, but these two effects are not causally related. It is, therefore, concluded that the prostaglandin-induced hemolysis is not directly associated with alterations of the $Ca^{++}$ content in the membrane.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.120-127
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• 1998

Peroxisome proliferators induce hepatic peroxisome proliferation and hepatic tumors in rodents. These chemicals increase the expression of the peroxisomal $\beta$-oxidation pathway and the cytochrome P-450 4A family, which metabolizes lipids, including eicosanoids. Peroxisome proliferators transiently induce increased cell proliferation in vivo. However, peroxisome proliferators are weakly mitogenic and are not co-mitogenic with epidermal growth factor (EGF) in cultured hepatocytes. Earlier study found that the peroxisome proliferator ciprofibrate is cornitogenic with eicosanoids. In order to study possible mechanisms of the comitogenicity of peroxisome proliferator ciprofibrate and eicosanoids' we hypothesized that the co-mitogenicity may result from synergistic or additive increases of second messengers in mitogenic signal pathways. We therefore examined the effect of the peroxisome proliferator ciprofibrate, prostaglandin $F_2_{\alpha}$($PGF_2{\alpha}$) and the combination of ciprofibrate and $PGF_2{\alpha}$ with or without growth factors on the protein kinase C (PKC) activity, and inositol-1, 4, 5-triphosphate ($IP_{3-}$) and intracellular calcium ($[Ca^{2+}]_i$) concentrations in cultured rat hepatocytes. The combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased particulate PKC activity. The combination of ciprofibrate and $PGF_2{\alpha}$ also significantly increased EGF, transforming growth factor-$\alpha$ ($TGF_2{\alpha}$) and hepatic growth factor (HGF)-induced particulate PKC activity. The combination of ciprofibrate and $PGF_2_\alpha$greatly increased $[Ca^{2+}]_i$. However, the increases of PKC activity and $[Ca^{2+}]_i$ by ciprofibrate and $PGF_2{\alpha}$ alone were much smaller. Neither ciprofibrate or $PGF_2{\alpha}$ alone nor the combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased the formation of $IP_3$. The combination of ciprofibrate and $PGF_2{\alpha}$, however, blocked the inhibitory effect of $TGF-{\beta}$ on particulate PKC activity and formation of $IP_3$ induced by EGF. These results show that co-mitogenicity of the peroxisome proliferator ciprofibrate and eicosanoids may result from the increase in particulate PKC activity and intracellular calcium concentration but not from the formation of $IP_3$.

• The Korean Journal of Pharmacology
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• v.20 no.1 s.34
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• pp.55-65
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• 1984

Comparative effects of $PGF_{2{\alpha}}$ and ouabain on the isolated rat(Sprague-Dowley) atria were studied. The isolated rat atria were prepared for isometric myography in the isolated organ bath containing Feigen's solution perfused with 95% $O_2$ and 5% $CO_2$, and the pH of the medium was maintained at 7.4. The cumulative concentration-response relationship revealed the positive inotropic effects of both drugs with the higher potency of $PGF_{2{\alpha}}$ and the higher efficacy of ouabain. $PGF_{2{\alpha}}$ showed a positive chronotropic effect, but ouabain showed a tendency of increasing the contraction rate. In low-Ca(1.4 mM) medium, the positive inotropic and chronotropic effect of $PGF_{2{\alpha}}$(by $3{\times}10^{-8}M$) were preponderant $(p<0.05{\sim}p<0.005)$ over those of ouabain(by $3{\times}10^{-3}M$). $Ca^{++}$-addition(cumulative, to 2.8, 4.2, 5.6, and 7.0 mM) into the medium evoked the more sensitive response in the $PGF_{2{\alpha}}$ group than in the ouabain group. In low-K(2.8 mM) medium, the $PGF_{2{\alpha}}a(3{\times}10^{-8}M)$ group and the ouabain$(3{\times}10^{-3}M)$ group showed similar tensions(DT and RT) and contraction rates. And both group showed significantly(p<0.05p<0.01) higher tensions and contraction rates than those of the control group. By the cumulative addition of the $K^+$(to 4.2, 5.6, 7.0 and 8.4 mM), only the DT of the $PGF_{2{\alpha}}$ group was sustained at signifcantly$(p<0.05{\sim}p<0.01)$ higher level than the DT of the control group. The $K^+$-addition inhibited the positive inotropic effect of ouabain significantly (p<0.05). The cumulative addition of lidocaine in high concentrations $(1{\times}10^{-5}\;to\;1{\times}10^{-3}M)$ evoked no significant influence on the intropic activities of $PGF_{2{\alpha}}$ and ouabain, but significant ${\beta}$-blockade with propranolol could not inhibit the positive intropic and chronotropic effect of $PGF_{2{\alpha}}$. In conclusion, it is presumed that $PGF_{2{\alpha}}$ may have some more active mechanism of accelerating the influx of $Ca^{++}$ across the cell membrane of the isolated rat atria as compared with ouabain, and the action site may be located at the cell membrane. As a supposition which needs further investigations, it is presumed that $PGF_{2{\alpha}}$ may have its specific membrane receptors on the atrial muscle or sinus node cells.

• Korean Journal of Animal Reproduction
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• v.3 no.2
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• pp.42-49
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• 1979

This experiment was carried out to clarify the practical use of farrowing induction with PGF2$\alpha$ in swine production. Total 320 heads of pregnant sow were used and the effects of administration time, dosage, administration method of PGF2$\alpha$ and parity of sow on the farrowing induction were investigated. The results obtained in this experiment were summarized as following: 1. Total 228 heads out of 240 head which were treated with PGF2$\alpha$ in order to farrow artificially were farrowed normally. the rate of farrowing induction was 95%. 2. Several farrowing symptoms such as restlessness, bloody eye, udder swelling, milk discharge and nest building for piglets were observed in a few minutes after administration of PGF2$\alpha$. 3. Artifical parturition of sow treated with PGF2 at the 113rd, 112nd, 111st, 110th and 109th day of pregnancy were induced 17.0$\pm$7.3, 24.2$\pm$7.0, 31.3$\pm$14.7, 43.0$\pm$12.2 and 62.2$\pm$15.7 hours after administration, and the duration of pregnancy was significantly (P<0.01) shortened by PGF2$\alpha$ anministration. 4. Minimum amount of PGF2$\alpha$ per head for effective farrowing inductin was considered to be more than 5mg, and the more the amount, the shorter time needed for farrowing induction was resulted. 5. Effective farrowing induction was obtained from the sow treated with PGF2$\alpha$ via vulvomucous rather than from the sow treated via intromuscular, and intervals from PGF2$\alpha$ administration to farrowing in 4th-6th farrowed sows were shorter than those of 1st-3rd farrowed sows but no significant difference was observed.

• 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.