The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform

Gonzalo Martinez De La Escalera - One of the best experts on this subject based on the ideXlab platform.

  • functional uncoupling between intraCellular calcium dynamics and secretion in the αt3 1 Gonadotropic Cell line
    Journal of Cellular Physiology, 1999
    Co-Authors: Citlali Trueta, Luis A Vaca, Carmen Clapp, Gonzalo Martinez De La Escalera
    Abstract:

    : Gonadotropin releasing hormone (GnRH) stimulates both transcription and secretion of the alpha subunit of the gonadotropins in a Ca2+-dependent fashion. In this study, we examined the role of Ca2+ as the signal coupling agonist occupancy of GnRH receptors to hormone secretion using the Gonadotropic Cell line alphaT3-1. Treatment of alphaT3-1 Cells for 60 min with GnRH (0.1-100 nM), veratridine (50 microM) or high K+ (56 mM) was completely ineffective in stimulating secretion. The lack of effect occurred in spite of a robust, specific, and dose-dependent biphasic [Ca2+]i response consisting of a rapid peak sensitive to thapsigargin (200 nM) followed by a smaller plateau sensitive to the extraCellular application of EGTA (5 mM). On the other hand, treatment of alphaT3-1 Cells with the Ca2+ ionophore ionomycin resulted in a significant dose-dependent stimulation of secretion and [Ca2+]i responses comparable to those elicited by GnRH. Binding assays revealed the presence of Ins(1,4,5)P3 receptors (Kd = 3.2 nM, Bmax = 50.5 fmol/mg protein) but not ryanodine receptors in alphaT3-1 Cell membranes. Together, these results show a functional uncoupling between the [Ca2+]i response and secretion in this Cell line, suggesting that the increase in [Ca2+]i triggered by GnRH and depolarization may be necessary but not sufficient to stimulate exocytosis.

Citlali Trueta - One of the best experts on this subject based on the ideXlab platform.

  • functional uncoupling between intraCellular calcium dynamics and secretion in the αt3 1 Gonadotropic Cell line
    Journal of Cellular Physiology, 1999
    Co-Authors: Citlali Trueta, Luis A Vaca, Carmen Clapp, Gonzalo Martinez De La Escalera
    Abstract:

    : Gonadotropin releasing hormone (GnRH) stimulates both transcription and secretion of the alpha subunit of the gonadotropins in a Ca2+-dependent fashion. In this study, we examined the role of Ca2+ as the signal coupling agonist occupancy of GnRH receptors to hormone secretion using the Gonadotropic Cell line alphaT3-1. Treatment of alphaT3-1 Cells for 60 min with GnRH (0.1-100 nM), veratridine (50 microM) or high K+ (56 mM) was completely ineffective in stimulating secretion. The lack of effect occurred in spite of a robust, specific, and dose-dependent biphasic [Ca2+]i response consisting of a rapid peak sensitive to thapsigargin (200 nM) followed by a smaller plateau sensitive to the extraCellular application of EGTA (5 mM). On the other hand, treatment of alphaT3-1 Cells with the Ca2+ ionophore ionomycin resulted in a significant dose-dependent stimulation of secretion and [Ca2+]i responses comparable to those elicited by GnRH. Binding assays revealed the presence of Ins(1,4,5)P3 receptors (Kd = 3.2 nM, Bmax = 50.5 fmol/mg protein) but not ryanodine receptors in alphaT3-1 Cell membranes. Together, these results show a functional uncoupling between the [Ca2+]i response and secretion in this Cell line, suggesting that the increase in [Ca2+]i triggered by GnRH and depolarization may be necessary but not sufficient to stimulate exocytosis.

Luis A Vaca - One of the best experts on this subject based on the ideXlab platform.

  • functional uncoupling between intraCellular calcium dynamics and secretion in the αt3 1 Gonadotropic Cell line
    Journal of Cellular Physiology, 1999
    Co-Authors: Citlali Trueta, Luis A Vaca, Carmen Clapp, Gonzalo Martinez De La Escalera
    Abstract:

    : Gonadotropin releasing hormone (GnRH) stimulates both transcription and secretion of the alpha subunit of the gonadotropins in a Ca2+-dependent fashion. In this study, we examined the role of Ca2+ as the signal coupling agonist occupancy of GnRH receptors to hormone secretion using the Gonadotropic Cell line alphaT3-1. Treatment of alphaT3-1 Cells for 60 min with GnRH (0.1-100 nM), veratridine (50 microM) or high K+ (56 mM) was completely ineffective in stimulating secretion. The lack of effect occurred in spite of a robust, specific, and dose-dependent biphasic [Ca2+]i response consisting of a rapid peak sensitive to thapsigargin (200 nM) followed by a smaller plateau sensitive to the extraCellular application of EGTA (5 mM). On the other hand, treatment of alphaT3-1 Cells with the Ca2+ ionophore ionomycin resulted in a significant dose-dependent stimulation of secretion and [Ca2+]i responses comparable to those elicited by GnRH. Binding assays revealed the presence of Ins(1,4,5)P3 receptors (Kd = 3.2 nM, Bmax = 50.5 fmol/mg protein) but not ryanodine receptors in alphaT3-1 Cell membranes. Together, these results show a functional uncoupling between the [Ca2+]i response and secretion in this Cell line, suggesting that the increase in [Ca2+]i triggered by GnRH and depolarization may be necessary but not sufficient to stimulate exocytosis.

Carmen Clapp - One of the best experts on this subject based on the ideXlab platform.

  • functional uncoupling between intraCellular calcium dynamics and secretion in the αt3 1 Gonadotropic Cell line
    Journal of Cellular Physiology, 1999
    Co-Authors: Citlali Trueta, Luis A Vaca, Carmen Clapp, Gonzalo Martinez De La Escalera
    Abstract:

    : Gonadotropin releasing hormone (GnRH) stimulates both transcription and secretion of the alpha subunit of the gonadotropins in a Ca2+-dependent fashion. In this study, we examined the role of Ca2+ as the signal coupling agonist occupancy of GnRH receptors to hormone secretion using the Gonadotropic Cell line alphaT3-1. Treatment of alphaT3-1 Cells for 60 min with GnRH (0.1-100 nM), veratridine (50 microM) or high K+ (56 mM) was completely ineffective in stimulating secretion. The lack of effect occurred in spite of a robust, specific, and dose-dependent biphasic [Ca2+]i response consisting of a rapid peak sensitive to thapsigargin (200 nM) followed by a smaller plateau sensitive to the extraCellular application of EGTA (5 mM). On the other hand, treatment of alphaT3-1 Cells with the Ca2+ ionophore ionomycin resulted in a significant dose-dependent stimulation of secretion and [Ca2+]i responses comparable to those elicited by GnRH. Binding assays revealed the presence of Ins(1,4,5)P3 receptors (Kd = 3.2 nM, Bmax = 50.5 fmol/mg protein) but not ryanodine receptors in alphaT3-1 Cell membranes. Together, these results show a functional uncoupling between the [Ca2+]i response and secretion in this Cell line, suggesting that the increase in [Ca2+]i triggered by GnRH and depolarization may be necessary but not sufficient to stimulate exocytosis.

John F. Leatherland - One of the best experts on this subject based on the ideXlab platform.

  • The development of monoclonal antibodies against salmon (Oncorhynchus kisutch and O. keta) pituitary hormones and their immunohistochemical identification.
    General and Comparative Endocrinology, 1990
    Co-Authors: K.j. Farbridge, G. Mcdonald-jones, C.l. Mclean, P.j. Lowry, Robert J. Etches, John F. Leatherland
    Abstract:

    Abstract Monoclonal antibodies (MCAs) directed against several salmon pituitary hormones were generated by the fusion of myeloma Cells with spleen Cells from mice that had been immunized with either chum salmon (Oncorhynchus keta) growth hormone (GH) or prolactin (PRL), or one of two purified protein preparations from coho salmon (O. kisutch) pituitaries. Hybridoma were cloned by limiting dilution and screened for MCA production using immunohistochemical procedures. MCAs were generated that bound specifically to GH, PRL, or Gonadotropic Cells. MCAs were generated that bound to either fine granular material or large globular inclusions in the cytoplasm of the “classical” strongly PAS-positive globular Gonadotropic Cell type found in mature fish. This suggests that these MCAs are directed against gonadotropin II (GTH II). A MCA was also generated that bound both granular and globular material in the globular gonadotrops and granular material in the weakly PAS-positive vesicular gonadotrops in pituitaries from mature fish and to a Cell type in immature rainbow trout pituitaries which is tentatively identified as the gonadotropin I (GTH I) Cell type. This MCA did not bind to thyrotrops in immature rainbow trout pituitaries.