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Yves Combarnous - One of the best experts on this subject based on the ideXlab platform.

  • choice of protocol for the in vivo bioassay of Equine Chorionic Gonadotropin ecg pmsg in immature female rats
    Theriogenology, 2019
    Co-Authors: Yves Combarnous, Julie Mariot, Lauriane Relav, Thi Mong Diep Nguyen, Daniele Klett
    Abstract:

    Abstract Equine Chorionic Gonadotropin (eCG) previously known as Pregnant Mare Serum Gonadotropin (PMSG) has been used for decades in regulating reproduction in various domestic animal species. Its use necessitates a good measurement of its bioactivity in commercial preparations. The EUROPEAN PHARMACOPEIA (EP 7.0) recommends 5–6 subcutaneous injections in immature female rats for the in vivo bioassay for eCG as in the case for measurement of FSH bioactivity in the Steelman & Pohley assay (1953). This recommendation is in marked contrast with the classical and long-time used PMSG assay of Cole & Erway (1941) that includes only one subcutaneous injection, 3 days before measurement of ovarian weight. As this difference introduces much confusion in the determination of eCG/PMSG bioactivity in commercial sources, we have performed parallel assays of several PMSG preparations, with both protocols. The single-injection protocol takes into account the long half-life of eCG in bloodstream and provokes an ovarian stimulation at lower concentrations than the multiple-injection protocol. As the single-injection protocol also mimicks the protocol used in cattle, it is preferable to the multiple-injection protocol of the current EP.

  • Choice of protocol for the in vivo bioassay of Equine Chorionic Gonadotropin (eCG / PMSG) in immature female rats
    Theriogenology, 2019
    Co-Authors: Yves Combarnous, Julie Mariot, Lauriane Relav, Thi Mong Diep Nguyen, Daniele Klett
    Abstract:

    Abstract Equine Chorionic Gonadotropin (eCG) previously known as Pregnant Mare Serum Gonadotropin (PMSG) has been used for decades in regulating reproduction in various domestic animal species. Its use necessitates a good measurement of its bioactivity in commercial preparations. The EUROPEAN PHARMACOPEIA (EP 7.0) recommends 5–6 subcutaneous injections in immature female rats for the in vivo bioassay for eCG as in the case for measurement of FSH bioactivity in the Steelman & Pohley assay (1953). This recommendation is in marked contrast with the classical and long-time used PMSG assay of Cole & Erway (1941) that includes only one subcutaneous injection, 3 days before measurement of ovarian weight. As this difference introduces much confusion in the determination of eCG/PMSG bioactivity in commercial sources, we have performed parallel assays of several PMSG preparations, with both protocols. The single-injection protocol takes into account the long half-life of eCG in bloodstream and provokes an ovarian stimulation at lower concentrations than the multiple-injection protocol. As the single-injection protocol also mimicks the protocol used in cattle, it is preferable to the multiple-injection protocol of the current EP.

  • topography of Equine Chorionic Gonadotropin epitopes relative to the luteinizing hormone and follicle stimulating hormone receptor interaction sites
    Molecular and Cellular Endocrinology, 1993
    Co-Authors: M Chopineau, Yves Combarnous, Mariechristine Maurel, Philippe Durand
    Abstract:

    Abstract In order to localize the epitopes of Equine Chorionic Gonadotropin (eCG) involved in interaction with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) receptors, we used 14 monoclonal anti-eCG antibodies (mAbs). Different effects of these mAbs on the bioactivities of eCG were observed in in vitro bioassays, but the effects of each mAb on the two bioactivities were similar for all but four mAbs. All mAbs were found to inhibit the binding of eCG to LH receptors except 3A3 mAb, in radioreceptor assay. Six mAbs, which were strong inhibitors of eCG binding to LH receptors and of both bioactivities, recognized the same area on the α subunit of eCG. All others, except 3A3, recognized epitopes close to the former, and close to each other. 3A3 mAb had a hyperstimulatory effect on FSH bioactivity, and was the only mAb that did not inhibit binding. It appeared to recognize a different epitopic area. These observations suggest that there is a main antigenic area on eCG, which corresponds to the interaction site of eCG with both receptors. It mostly involves the α subunit and to a lesser extent the β subunit.

  • Enzyme Immunoassay (EIA) for Equine Chorionic Gonadotropin / Pregnant Mare Serum Gonadotropin (eCG/PMSG)
    Journal of Immunoassay, 1992
    Co-Authors: Francois Lecompte, Yves Combarnous
    Abstract:

    Abstract A simple, accurate, sensitive enzyme immunoassay (EIA) has been developed that permits the measurement of Equine Chorionic Gonadotropin activity in pregnant mare plasmas or serums as well as in commercial and highly-purified preparations. This assay is specific for eCG and eLH which share the same polypeptide structure but differ in their oligosaccharidic chains. The more important result is that this EIA has been found to be give data in very close agreement with the in vivo assay. Therefore this very rapid and convenient assay can be used to measure the activity of eCG/PMSG in pregnant mares serums in in-field conditions as well as in crude or highly-purified preparations.

  • immunochemical study of Equine Chorionic Gonadotropin ecg pmsg antigenic determinants on α and β subunits
    Biochimica et Biophysica Acta, 1992
    Co-Authors: Mariechristine Maurel, Jeanmichel Bidart, Yves Combarnous
    Abstract:

    Abstract In the present study we have established an immunochemical mapping of Equine Chorionic Gonadotropin (eCG/PMSG) using three monoclonal antibodies (mAbs), namely the antibodies ECG01, E10 and D7, raised against the native hormone. These antibodies do not bind to reduced, alkylated hormone, suggesting that they recognize discontinuous rather than continuous epitopes. We have also assessed the reactivity of mAbs towards human CG, and ovine, porcine, Equine and bovine LH and FSH. The antigenic determinant recognized by ECG01 is localized on the α-subunit of Equine Gonadotropins and of human CG and LH. The epitopes recognized by E10 and D7 mAbs appear to be very similar and are present on the β-subunit of eCG and of LHs from all species tested, except hLH, as well as on porcine and Equine FSHs. Attempts to specify the amino-acid residues involved in these epitopes suggest that ECG01 mAb might preferentially bind to residues around position 70 whereas the region around disulfide bridges Cys-88-Cys-90 might be involved in the epitopes recognized by D7 and E10 mAbs. Topographical relationships of epitopes show that ECG01 mAb never binds to eCG simultaneously with either D7 or E10 mAbs. Furthermore, simultaneous binding of D7 and E10 mAbs on eCG could not be achieved. Thus, these three epitopes appear to be closely located on the surface of eCG. Finally, ECG01 mAb inhibits eCG binding to LH and FSH receptors, suggesting that its antigenic site is closely related to hormone-receptor interaction site(s).

Mariechristine Maurel - One of the best experts on this subject based on the ideXlab platform.

  • selective modulation of follicle stimulating hormone signaling pathways with enhancing Equine Chorionic Gonadotropin antibody immune complexes
    Endocrinology, 2010
    Co-Authors: Vanessa Wehbi, Jeremy Decourtye, Vincent Piketty, Guillaume Durand, Eric Reiter, Mariechristine Maurel
    Abstract:

    The injection of Equine Chorionic Gonadotropin (eCG) in dairy goats induces the production of anti-eCG antibodies (Abs) in some females. We have previously shown that Abs negatively modulate the LH and FSH-like bioactivities of eCG, in most cases, compromising fertility in treated females. Surprisingly, we found out that some anti-eCG Abs improved fertility and prolificity of the treated females, in vivo. These Abs, when complexed with eCG, enhanced LH and FSH ability to induce steroidogenesis on specific target cells, in vitro. In the present study, we analyzed the impact of three eCG/anti-eCG Ab-enhancing complexes on two transduction mechanisms triggered by the FSH receptor: guanine nucleotide-binding protein αS-subunit/cAMP/protein kinase A (PKA) and β-arrestin-dependent pathways, respectively. In all cases, significant enhancing effects were observed on ERK phosphorylation compared with eCG alone. However, cAMP production and PKA activation induced by eCG could be differently modulated by Abs. By usi...

  • Selective Modulation of Follicle-Stimulating Hormone Signaling Pathways With Enhancing Equine Chorionic Gonadotropin/antibody Immune Complexes
    Endocrinology, 2010
    Co-Authors: Vanessa Wehbi, Jeremy Decourtye, Vincent Piketty, Guillaume Durand, Eric Reiter, Mariechristine Maurel
    Abstract:

    The injection of Equine Chorionic Gonadotropin (eCG) in dairy goats induces the production of anti-eCG antibodies (Abs) in some females. We have previously shown that Abs negatively modulate the LH and FSH-like bioactivities of eCG, in most cases, compromising fertility in treated females. Surprisingly, we found out that some anti-eCG Abs improved fertility and prolificity of the treated females, in vivo. These Abs, when complexed with eCG, enhanced LH and FSH ability to induce steroidogenesis on specific target cells, in vitro. In the present study, we analyzed the impact of three eCG/anti-eCG Ab-enhancing complexes on two transduction mechanisms triggered by the FSH receptor: guanine nucleotide-binding protein αS-subunit/cAMP/protein kinase A (PKA) and β-arrestin-dependent pathways, respectively. In all cases, significant enhancing effects were observed on ERK phosphorylation compared with eCG alone. However, cAMP production and PKA activation induced by eCG could be differently modulated by Abs. By usi...

  • topography of Equine Chorionic Gonadotropin epitopes relative to the luteinizing hormone and follicle stimulating hormone receptor interaction sites
    Molecular and Cellular Endocrinology, 1993
    Co-Authors: M Chopineau, Yves Combarnous, Mariechristine Maurel, Philippe Durand
    Abstract:

    Abstract In order to localize the epitopes of Equine Chorionic Gonadotropin (eCG) involved in interaction with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) receptors, we used 14 monoclonal anti-eCG antibodies (mAbs). Different effects of these mAbs on the bioactivities of eCG were observed in in vitro bioassays, but the effects of each mAb on the two bioactivities were similar for all but four mAbs. All mAbs were found to inhibit the binding of eCG to LH receptors except 3A3 mAb, in radioreceptor assay. Six mAbs, which were strong inhibitors of eCG binding to LH receptors and of both bioactivities, recognized the same area on the α subunit of eCG. All others, except 3A3, recognized epitopes close to the former, and close to each other. 3A3 mAb had a hyperstimulatory effect on FSH bioactivity, and was the only mAb that did not inhibit binding. It appeared to recognize a different epitopic area. These observations suggest that there is a main antigenic area on eCG, which corresponds to the interaction site of eCG with both receptors. It mostly involves the α subunit and to a lesser extent the β subunit.

  • immunochemical study of Equine Chorionic Gonadotropin ecg pmsg antigenic determinants on α and β subunits
    Biochimica et Biophysica Acta, 1992
    Co-Authors: Mariechristine Maurel, Jeanmichel Bidart, Yves Combarnous
    Abstract:

    Abstract In the present study we have established an immunochemical mapping of Equine Chorionic Gonadotropin (eCG/PMSG) using three monoclonal antibodies (mAbs), namely the antibodies ECG01, E10 and D7, raised against the native hormone. These antibodies do not bind to reduced, alkylated hormone, suggesting that they recognize discontinuous rather than continuous epitopes. We have also assessed the reactivity of mAbs towards human CG, and ovine, porcine, Equine and bovine LH and FSH. The antigenic determinant recognized by ECG01 is localized on the α-subunit of Equine Gonadotropins and of human CG and LH. The epitopes recognized by E10 and D7 mAbs appear to be very similar and are present on the β-subunit of eCG and of LHs from all species tested, except hLH, as well as on porcine and Equine FSHs. Attempts to specify the amino-acid residues involved in these epitopes suggest that ECG01 mAb might preferentially bind to residues around position 70 whereas the region around disulfide bridges Cys-88-Cys-90 might be involved in the epitopes recognized by D7 and E10 mAbs. Topographical relationships of epitopes show that ECG01 mAb never binds to eCG simultaneously with either D7 or E10 mAbs. Furthermore, simultaneous binding of D7 and E10 mAbs on eCG could not be achieved. Thus, these three epitopes appear to be closely located on the surface of eCG. Finally, ECG01 mAb inhibits eCG binding to LH and FSH receptors, suggesting that its antigenic site is closely related to hormone-receptor interaction site(s).

  • Immunochemical study of Equine Chorionic Gonadotropin (eCG/PMSG): antigenic determinants on α- and β-subunits
    Biochimica et Biophysica Acta, 1992
    Co-Authors: Mariechristine Maurel, Jeanmichel Bidart, Yves Combarnous
    Abstract:

    Abstract In the present study we have established an immunochemical mapping of Equine Chorionic Gonadotropin (eCG/PMSG) using three monoclonal antibodies (mAbs), namely the antibodies ECG01, E10 and D7, raised against the native hormone. These antibodies do not bind to reduced, alkylated hormone, suggesting that they recognize discontinuous rather than continuous epitopes. We have also assessed the reactivity of mAbs towards human CG, and ovine, porcine, Equine and bovine LH and FSH. The antigenic determinant recognized by ECG01 is localized on the α-subunit of Equine Gonadotropins and of human CG and LH. The epitopes recognized by E10 and D7 mAbs appear to be very similar and are present on the β-subunit of eCG and of LHs from all species tested, except hLH, as well as on porcine and Equine FSHs. Attempts to specify the amino-acid residues involved in these epitopes suggest that ECG01 mAb might preferentially bind to residues around position 70 whereas the region around disulfide bridges Cys-88-Cys-90 might be involved in the epitopes recognized by D7 and E10 mAbs. Topographical relationships of epitopes show that ECG01 mAb never binds to eCG simultaneously with either D7 or E10 mAbs. Furthermore, simultaneous binding of D7 and E10 mAbs on eCG could not be achieved. Thus, these three epitopes appear to be closely located on the surface of eCG. Finally, ECG01 mAb inhibits eCG binding to LH and FSH receptors, suggesting that its antigenic site is closely related to hormone-receptor interaction site(s).

José Antonio Guimarães Aleixo - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Equine Chorionic Gonadotropin on weaning-to-estrus interval and estrus duration in early-weaned, primiparous, female swine.
    Journal of Animal Science, 1999
    Co-Authors: Thomaz Lucia, Marcio Nunes Corrêa, João Carlos Deschamps, Ivan A. Peruzzo, Jairo E. M. Matheus, José Antonio Guimarães Aleixo
    Abstract:

    : The weaning-to-estrus interval (WEI) influences the total nonproductive days (NPD) accumulated by the breeding herd and affects herd productivity. Short lactation lengths (LL) are commonly followed by prolonged WEI, which are also associated with short estrus duration (ED). Equine Chorionic Gonadotropin treatment is a tool that has been used to reduce WEI, especially for low-parity females. The objectives for this study were to evaluate the effect of LL on the association between WEI and ED and to estimate the effects of postweaning eCG administration on WEI and ED for early-weaned females. Two treatments (TREAT) consisting of 750 IU of eCG (n = 96) or control (n = 77) were applied 1 d after weaning to first-parity, weaned females. The study was conducted on a commercial farm having a target LL of 18 d. Estrus detection was conducted three times daily, and estrus duration was determined as the interval between the first and the last positive response to back pressure. Analyses of variance were conducted to estimate the effects of LL and TREAT on WEI and the effects of TREAT and WEI on estrus duration. Mean LL was 17.9+/-1.7 d, mean WEI was 106.6+/-29.2 h, and mean estrus duration was 55.9+/-15.5 h. Even though the frequency of short WEI tended to increase with longer LL, mean WEI was shortest for females weaned after 18 d and longest for those weaned after 20 d (P

  • influence of Equine Chorionic Gonadotropin on weaning to estrus interval and estrus duration in early weaned primiparous female swine
    Journal of Animal Science, 1999
    Co-Authors: Thomaz Lucia, Marcio Nunes Corrêa, João Carlos Deschamps, Ivan A. Peruzzo, Jairo E. M. Matheus, José Antonio Guimarães Aleixo
    Abstract:

    : The weaning-to-estrus interval (WEI) influences the total nonproductive days (NPD) accumulated by the breeding herd and affects herd productivity. Short lactation lengths (LL) are commonly followed by prolonged WEI, which are also associated with short estrus duration (ED). Equine Chorionic Gonadotropin treatment is a tool that has been used to reduce WEI, especially for low-parity females. The objectives for this study were to evaluate the effect of LL on the association between WEI and ED and to estimate the effects of postweaning eCG administration on WEI and ED for early-weaned females. Two treatments (TREAT) consisting of 750 IU of eCG (n = 96) or control (n = 77) were applied 1 d after weaning to first-parity, weaned females. The study was conducted on a commercial farm having a target LL of 18 d. Estrus detection was conducted three times daily, and estrus duration was determined as the interval between the first and the last positive response to back pressure. Analyses of variance were conducted to estimate the effects of LL and TREAT on WEI and the effects of TREAT and WEI on estrus duration. Mean LL was 17.9+/-1.7 d, mean WEI was 106.6+/-29.2 h, and mean estrus duration was 55.9+/-15.5 h. Even though the frequency of short WEI tended to increase with longer LL, mean WEI was shortest for females weaned after 18 d and longest for those weaned after 20 d (P<.05). The WEI for females receiving eCG (98.7+/-2.7 h) was shorter (P = .0001) than that for control females (121.5+/-3.3 h). The WEI was also affected by a LL x TREAT interaction (P = .0014), indicating that the interval was longer (P<.05) for control females weaned after 17 and 20+ d than for other females. The LL and TREAT did not affect estrus duration (P = .20 and P = .157, respectively). However, estrus duration was reduced as the WEI increased (P = .0001), and it was also influenced by a WEI x TREAT interaction (P = .024). A linear regression model estimated that the association between WEI and estrus duration was stronger in the eCG group than in the control group (R2 = .51 and .15, respectively; both P<.001). In conclusion, the use of eCG postweaning was associated with more precise prediction of estrus duration as a function of the WEI and allows optimization of breeding management in early-weaned, primiparous females.

Eimei Sato - One of the best experts on this subject based on the ideXlab platform.

  • Increased ovarian follicular angiogenesis and dynamic changes of follicular vascular plexuses induced by Equine Chorionic Gonadotropin in the gilt
    Cell and Tissue Research, 2004
    Co-Authors: Jin-yi Jiang, Takashi Shimizu, Hiroshi Sasada, Benjamin K. Tsang, Eimei Sato
    Abstract:

    Follicular angiogenesis and capillary degeneration are crucial ovarian processes in folliculogenesis. The present study was conducted to assess the changes in population of follicular vascular plexuses with different capillary status in prepubertal gilts 72 h after Equine Chorionic Gonadotropin (eCG) (1,250 IU) treatment, using combined vascular corrosion casting and scanning electron microscopy. Follicular fluid concentrations of estradiol, progesterone and vascular endothelial growth factor (VEGF) were determined to confirm the follicular status. Based on the proliferative or degenerative characteristics of their capillaries, follicles were classified into three categories: active angiogenesis, low angiogenesis and degeneration. Irrespective of exogenous Gonadotropin treatment in vivo, small follicular vascular plexuses (5 mm) plexuses showed only active angiogenesis or degeneration. eCG treatment significantly increased the population of large, but decreased that of small follicular plexuses. Most large follicular vascular plexuses showed active angiogenesis with higher follicular fluid estradiol:progesterone ratios and VEGF concentration. eCG also increased the percentage of medium follicular plexuses with active angiogenesis. The populations of small follicular plexuses with active angiogenesis were higher in controls, but decreased after eCG treatment. However, treatment of gilts with the Gonadotropin increased the percentage of small plexuses (

  • increased ovarian follicular angiogenesis and dynamic changes of follicular vascular plexuses induced by Equine Chorionic Gonadotropin in the gilt
    Cell and Tissue Research, 2004
    Co-Authors: Jin-yi Jiang, Takashi Shimizu, Hiroshi Sasada, Benjamin K. Tsang, Eimei Sato
    Abstract:

    Follicular angiogenesis and capillary degeneration are crucial ovarian processes in folliculogenesis. The present study was conducted to assess the changes in population of follicular vascular plexuses with different capillary status in prepubertal gilts 72 h after Equine Chorionic Gonadotropin (eCG) (1,250 IU) treatment, using combined vascular corrosion casting and scanning electron microscopy. Follicular fluid concentrations of estradiol, progesterone and vascular endothelial growth factor (VEGF) were determined to confirm the follicular status. Based on the proliferative or degenerative characteristics of their capillaries, follicles were classified into three categories: active angiogenesis, low angiogenesis and degeneration. Irrespective of exogenous Gonadotropin treatment in vivo, small follicular vascular plexuses ( 5 mm) plexuses showed only active angiogenesis or degeneration. eCG treatment significantly increased the population of large, but decreased that of small follicular plexuses. Most large follicular vascular plexuses showed active angiogenesis with higher follicular fluid estradiol:progesterone ratios and VEGF concentration. eCG also increased the percentage of medium follicular plexuses with active angiogenesis. The populations of small follicular plexuses with active angiogenesis were higher in controls, but decreased after eCG treatment. However, treatment of gilts with the Gonadotropin increased the percentage of small plexuses (<1.0 mm) with low angiogenesis and those (1–3.9 mm) with extensive capillary degeneration. These findings are consistent with the hypothesis that angiogenesis is involved in selection and growth of small follicles in gilts under the regulation of Gonadotropin.

Benjamin K. Tsang - One of the best experts on this subject based on the ideXlab platform.

  • Increased ovarian follicular angiogenesis and dynamic changes of follicular vascular plexuses induced by Equine Chorionic Gonadotropin in the gilt
    Cell and Tissue Research, 2004
    Co-Authors: Jin-yi Jiang, Takashi Shimizu, Hiroshi Sasada, Benjamin K. Tsang, Eimei Sato
    Abstract:

    Follicular angiogenesis and capillary degeneration are crucial ovarian processes in folliculogenesis. The present study was conducted to assess the changes in population of follicular vascular plexuses with different capillary status in prepubertal gilts 72 h after Equine Chorionic Gonadotropin (eCG) (1,250 IU) treatment, using combined vascular corrosion casting and scanning electron microscopy. Follicular fluid concentrations of estradiol, progesterone and vascular endothelial growth factor (VEGF) were determined to confirm the follicular status. Based on the proliferative or degenerative characteristics of their capillaries, follicles were classified into three categories: active angiogenesis, low angiogenesis and degeneration. Irrespective of exogenous Gonadotropin treatment in vivo, small follicular vascular plexuses (5 mm) plexuses showed only active angiogenesis or degeneration. eCG treatment significantly increased the population of large, but decreased that of small follicular plexuses. Most large follicular vascular plexuses showed active angiogenesis with higher follicular fluid estradiol:progesterone ratios and VEGF concentration. eCG also increased the percentage of medium follicular plexuses with active angiogenesis. The populations of small follicular plexuses with active angiogenesis were higher in controls, but decreased after eCG treatment. However, treatment of gilts with the Gonadotropin increased the percentage of small plexuses (

  • increased ovarian follicular angiogenesis and dynamic changes of follicular vascular plexuses induced by Equine Chorionic Gonadotropin in the gilt
    Cell and Tissue Research, 2004
    Co-Authors: Jin-yi Jiang, Takashi Shimizu, Hiroshi Sasada, Benjamin K. Tsang, Eimei Sato
    Abstract:

    Follicular angiogenesis and capillary degeneration are crucial ovarian processes in folliculogenesis. The present study was conducted to assess the changes in population of follicular vascular plexuses with different capillary status in prepubertal gilts 72 h after Equine Chorionic Gonadotropin (eCG) (1,250 IU) treatment, using combined vascular corrosion casting and scanning electron microscopy. Follicular fluid concentrations of estradiol, progesterone and vascular endothelial growth factor (VEGF) were determined to confirm the follicular status. Based on the proliferative or degenerative characteristics of their capillaries, follicles were classified into three categories: active angiogenesis, low angiogenesis and degeneration. Irrespective of exogenous Gonadotropin treatment in vivo, small follicular vascular plexuses ( 5 mm) plexuses showed only active angiogenesis or degeneration. eCG treatment significantly increased the population of large, but decreased that of small follicular plexuses. Most large follicular vascular plexuses showed active angiogenesis with higher follicular fluid estradiol:progesterone ratios and VEGF concentration. eCG also increased the percentage of medium follicular plexuses with active angiogenesis. The populations of small follicular plexuses with active angiogenesis were higher in controls, but decreased after eCG treatment. However, treatment of gilts with the Gonadotropin increased the percentage of small plexuses (<1.0 mm) with low angiogenesis and those (1–3.9 mm) with extensive capillary degeneration. These findings are consistent with the hypothesis that angiogenesis is involved in selection and growth of small follicles in gilts under the regulation of Gonadotropin.