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Characterization of the receptor for gonadotropin-releasing hormone in the pituitary of the African catfish,Clarias gariepinus

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Abstract

Receptors for gonadotropin-releasing hormone (GnRH) were characterized using a radioligand prepared from a superactive analog of salmon GnRH (sGnRH), D-Arg6-Pro9-sGnRH-NEt (sGnRHa). Binding of125I-sGnRHa to catfish pituitary membrane fractions reached equilibrium after 2 h incubation at 4°C. Displacement experiments with several GnRH analogs as well as other peptides, demonstrated the specificity of125I-sGnRHa binding. Specific binding was enhanced in the presence of the cation chelator ethylene bis (oxyethylenenitrilo) tetra-acetic acid (EGTA), indicating an inhibitory effect of cations on GnRH-receptor binding. The binding of125I-sGnRHa to pituitary membranes was found to be saturable at radioligand concentrations of 5 nM and above. A Scatchard analysis of the saturation data suggested the presence of a single class of high-affinity binding sites (Ka=0.901±0.06×109M−1, Bmax=1678±150 fmol/mg protein). A comparative study on125I-sGnRHa binding to pituitary membrane fractions of male and female catfish, indicated that there were no differences in binding affinity and binding capacity between both sexes. The results demonstrate the presence of specific, saturable GnRH receptors in the African catfish pituitary.

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References cited

  • Andries, M. and Denef, C. 1986. Characterization of luteinizing hormone-releasing hormone receptor binding in rat pituitary cell monolayer cultures: influence of intercellular communication. Mol. Cell. Endocrinol. 44: 147–158.

    Google Scholar 

  • Bradford, M. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the princeiple of protein-dye binding. Anal. Biochem. 72: 248–254.

    Google Scholar 

  • Chang, J.P., Mackenzie, D.S., Gould, D.R. and Peter, R.E. 1984. Effects of dopamine and norepinephrine onin vitro spontaneous and gonadotropin-releasing hormone-induced gonadotropin release by dispersed cells or fragments of the goldfish pituitary. Life Sci. 35: 2027–2033.

    Google Scholar 

  • Clayton, R.N., Shakespear, R.A., Duncan, J.A. and Marshall, J.C. with appendix by Munson, P.J. and Rodbard, D. 1979. Radioiodinated nondegradable GnRH analogs: new probes for the investigation of pituitary GnRH receptors. Endocrinology 105: 1369–1381.

    Google Scholar 

  • Clayton, R.N., Solano, A.R., Garcia-Vela, A., Dufau, M.L. and Catt, K.J. 1980. Regulation of pituitary receptors for gonadotropin-releasing hormone during the rat estrous cycle. Endocrinology 107: 699–706.

    Google Scholar 

  • Conn, P.M., Marian, J., McMillan, M., Stern, J., Rogers, D., Hamby, M., Penna, A. and Grant, E. 1981. Gonadotropinreleasing hormone action in the pituitary: a three step mechanism. Endocrine Rev. 2: 174–185.

    Google Scholar 

  • Crim, L.W., Arnaud, R.St., Lavoie, M. and Labrie, F. 1988. A study of LHRH receptors in the pituitary gland of the winter flounder (Pseudopleuronectes americanus Walbaum). Gen. Comp. Endocrinol. (In press).

  • De Leeuw, R., Resink, J.W., Rooyakkers, E.J.M. and Goos, H.J.Th., 1985. Pimozide modulates the luteinizing hormone-releasing hormone effect on gonadotrophin release in the African catfish,Clarias lazera. Gen. Comp. Endocrinol. 58: 120–127.

    Google Scholar 

  • De Leeuw, R., Goos, H.J.Th. and Van Oordt, P.G.W.J. 1986. The dopaminergic inhibition of the gonadotropin-releasing hormone-induced gonadotropin release: An in vitro study with fragments and cell suspensions from pituitaries of the African catfish,Clarias gariepinus (Burchell). Gen. Comp. Endocrinol. 63: 171–177.

    Google Scholar 

  • De Leeuw, R., Goos, H.J.Th. and Van Oordt, P.G.W.J. 1987a. The regulation of gonadotropin release by neurohormones and gonadal steroids in the African catfish,Clarias gariepinus. Aquaculture 63: 43–58.

    Google Scholar 

  • De Leeuw, R., Smit-Van Dijk, W., Van't Veer, C., Beumer, P., Goos, H.J.Th. and Van Oordt, P.G.W.J. 1987b. Gonadotropin-releasing hormone agonists: their relative binding affinity and biological activity in the African catfish,Clarias gariepinus. Third International Symposium on Reproductive Physiology of Fish. St. John's, New Foundland, Canada.

  • Goos, H.J.Th., De Leeuw, R., De Zoeten-Kamp, C., Peute, J. and Blähser, S. 1985. Gonadotropin-releasing hormone-immunoreactive neuronal structures in the brain and pituitary of the African catfish,Clarias gariepinus (Burchell). Cell Tiss. Res. 241: 593–596.

    Google Scholar 

  • Gorospe, W.C. and Conn, P.M. 1987. Pituitary regulation by gonadotropin-releasing hormone (GnRH): Gonadotropin secretion, receptor numbers, and target cell sensitivity. Endocrinology (In press).

  • Habibi, H.R., Peter, R.E., Sokolowska, M., Rivier, J.E. and Vale, W.W. 1987. Characterization of gonadotropin-releasing hormone (GnRH) binding to pituitary receptors in goldfish,Carassius auratus. Biol. Reprod. 36: 844–853.

    Google Scholar 

  • Hazum, E. 1981. Some characteristics of GnRH receptors on rat pituitary membranes: differences between agonist and antagonist. Mol. Cell. Endocrinol. 23: 275–281.

    Google Scholar 

  • King, J.A. and Millar, R.P. 1985. Multiple molecular forms of gonadotropin-releasing hormone in teleost fish brain. Peptides 6: 689–694.

    Google Scholar 

  • Koch, Y., Baram, T., Hazum, E. and Fridkin, M. 1977. Resistance to enzymic degradation of LHRH analogs possessing increased biological activity. Biochem. Biophys. Res. Commun. 74: 488–491.

    Google Scholar 

  • Koiter, T.R., Denef, C., Andries, M., Moes, H. and Schuiling, G.A. 1986. The prolonged action of the LHRH agonist Buserelin (HOE 766) may be due to prolonged binding to the LHRH receptor. Life Sci. 39: 443–452.

    Google Scholar 

  • Loumaye, E., Naor, Z. and Catt, K. J. 1982. Binding affinity and biological activity of gonadotropin-releasing hormone agonists in isolated pituitary cells. Endocrinology 111: 730–736.

    Google Scholar 

  • Mackenzie, D.S., Gould, D.R., Peter, R.E., Rivier, J. and Vale, W.W. 1984. Response of superfused goldfish pituitary fragments to mammalian and salmon gonadotropin-releasing hormones. Life Sci. 35: 2019–2026.

    Google Scholar 

  • Marian, J. and Conn, P.M. 1980. The calcium requirement in GnRH-stimulated LH release is not mediated through a specific action on the receptor. Life Sci. 27: 87–92.

    Google Scholar 

  • Marian, J., Cooper, R.L. and Conn, P.M. 1981. Regulation of the rat pituitary GnRH-receptor. Mol. Pharmacol. 19: 399–405.

    Google Scholar 

  • Meidan, R., Aroya, N.B. and Koch, Y. 1982. Variation in the number of LHRH receptors correlated with altered reponsiveness to LHRH. Life Sci. 30: 535–541.

    Google Scholar 

  • Munson, P.M. and Rodbard, D. 1980. Ligand: a versatile computerized approach for characterization of ligand-binding system. Anal. Biochem. 107: 220–239.

    Google Scholar 

  • Naor, Z., Clayton, R.N. and Catt, K.J. 1980. Characterization of gonadotropin-releasing hormone receptors in cultured rat pituitary cells. Endocrinology 107: 1144–1152.

    Google Scholar 

  • Pedroza, E., Vilchez-Martinez, J.A., Fishback, J., Arimura, A. and Schally, A.V. 1977. Binding capacity of luteinizing hormone-releasing hormone and its analogues for pituitary binding sites. Biochem. Biophys. Res. Commun. 79: 234–238.

    Google Scholar 

  • Peter, R.E. 1983. The brain and neurohormones in teleost reproduction.In: Fish Physiology, Vol. IX, pp 97–135. Edited by W.S. Hoar, D.J. Randall and E.M. Donaldson. Academic Press, New York.

    Google Scholar 

  • Peter, R.E., Nahorniak, C.S., Sokolowska, M., Chang, J.P., Rivier, J.E., Vale, W.W., King, J.A. and Millar, R.P. 1985. Structure-activity relationship of mammalian, chicken and salmon gonadotropin releasing hormones in vivo in goldfish. Gen. Comp. Endocrinol. 58: 231–242.

    Google Scholar 

  • Peute, J., Schild, R.G., Schild, V.A., Buijs, R.M., Van Asselt, L.A.C. and Van Oordt, P.G.W.J. 1987. Immunocytochemical evidence for peptidergic (GnRH) and dopaminergic innervation of the gonadotropic cells in the pituitary of the African catfish,Clarias gariepinus. Gen. Comp. Endocrinol. In Press.

  • Powell, R.C., Millar, R.P. and King, J.A. 1986. Diverse molecular forms of ganadotropin-releasing hormone in an elasmobranch and a teleost fish. Gen. Comp. Endocrinol. 63: 77–85.

    Google Scholar 

  • Sherwood, N., Eiden, L., Brownstein, M., Spiess, J., Rivier, J. and Vale, W. 1983. Characterization of teleost gonadotropin-releasing hormone. Proc. Nat. Acad. Sci. 80: 2794–2798.

    Google Scholar 

  • Sherwood, N.M., Harvey, B., Brownstein, M.J. and Eiden, L.E. 1984. Gonadotropin-releasing hormone (Gn-RH) in striped mulled (Mugil cephalus), milkfish (Chanos chanos), and rainbow trout (Salmo gairdneri): Comparison with salmon Gn-RH. Gen. Comp. Endocrinol. 55: 174–181.

    Google Scholar 

  • Spona, J. 1973. LH-RH interaction with the pituitary plasma membrane. FEBS Lett. 34: 24–26.

    Google Scholar 

  • Weil, C., Hansens, P., Hyam, D., Le Gac, F., Breton, B. and Crim, L.W. 1986. Use of pituitary cells in primary culture to study the regulation of gonadotropin hormone (GTH) secretion in rainbow trout: setting up and validating the system as assessed by its responsiveness to mammalian and salmon gonadotropin-releasing hormone. Gen. Comp. Endocrinol. 62: 202–209.

    Google Scholar 

  • Wu, P., Ackland, J.F., Ling, N. and Jackson, I.M.D. 1986. Purification and characterization of luteinizing hormone-releasing hormone from codfish brain. Reg. Pept. 15: 311–321.

    Google Scholar 

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Authors and Affiliations

  1. Department of Experimental Zoology, Research group for Comparative Endocrinology, University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands

    R. De Leeuw, C. Van't Veer, H. J. Th. Goos & P. G. W. J. Van Oordt

  2. Department of Pharmacology, University of Iowa, College of Medicine, 52242, Iowa City, Iowa, USA

    P. M. Conn

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  1. R. De Leeuw
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  2. P. M. Conn
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  3. C. Van't Veer
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  4. H. J. Th. Goos
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  5. P. G. W. J. Van Oordt
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De Leeuw, R., Conn, P.M., Van't Veer, C. et al. Characterization of the receptor for gonadotropin-releasing hormone in the pituitary of the African catfish,Clarias gariepinus . Fish Physiol Biochem 5, 99–107 (1988). https://doi.org/10.1007/BF01875646

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