Identification and characterization of a corticotrophin-releasing hormone receptor in human placenta

Clifton VL, Owens PC, Robinson PJ, Smith R. Identification and characterization of a corticotrophinreleasing hormone receptor in human placenta. Eur J Endocrinol 1995;133:591–7. ISSN 0804–4643 Corticotrophin-releasing hormone (CRH) causes vasodilatation in the human fetal–placental circulation and has paracrine actions in placental tissue, suggesting that CRH receptors may be present in the human placenta. We have now identified and characterized placental CRH binding sites and compared them to those described previously in human myometrium and rat pituitary. Radiolabelled ovine CRH binding to placental membranes was pH-, time-, temperature- and divalent cation-dependent and was reversible in the presence of 1 μmol/l unlabelled ovine CRH. Scatchard analysis of placentae delivered vaginally or by elective caesarean section revealed dissociation constants (Kd) of 214.5 ± 84 pmol/l (N = 8) and 45.4 ± 23.9 pmol/l (N = 9), respectively. The Kd for caesarean placental binding sites was similar to that of human myometrium (59.6 pmol/l, N = 3) and rat pituitary (82.5 pmol/l, N = 3) receptors. However, in vaginally delivered placentae the CRH binding sites had a much lower affinity (p < 0.05). The receptor densities (Bmax) of vaginally delivered and caesarean-delivered placentae were 28.6 ± 9.6 and 6.1 ± 2.8 fmol/mg, respectively (p < 0.05). Chemical cross-linking studies using disuccinimidyl suberate indicated that the molecular weight of the CRH receptor in the placenta and rat pituitary is 75 kD. We conclude that there is a high-affinity population of CRH binding sites in the human placenta that are physicochemically similar to pituitary and myometrial CRH receptors. The CRH receptor properties in the placenta change in response to labour, when CRH levels in maternal blood are highest, suggesting that placental CRH may regulate its receptor. R Smith, Endocrinology Unit, John Hunter Hospital, Locked Bag 1, Hunter Regional Mail Centre, Newcastle, NSW 2310, Australia

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Isolation and characterization of cDNAs encoding the rat pituitary gonadotropin-releasing hormone receptor

Biochemical and Biophysical Research Communications ◽

10.1016/0006-291x(92)90266-n ◽

1992 ◽

Vol 189 (3) ◽

pp. 1645-1652 ◽

Cited By ~ 100

Author(s):

Ursula B. Kaiser ◽

Dayao Zhao ◽

Guemalli R. Cardona ◽

William W. Chin

Keyword(s):

Hormone Receptor ◽

Gonadotropin Releasing Hormone ◽

Releasing Hormone ◽

Isolation And Characterization ◽

Pituitary Gonadotropin ◽

Rat Pituitary ◽

Gonadotropin Releasing Hormone Receptor

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Characterization of Corticotropin-Releasing Hormone Binding Sites in the Human Placenta

Journal of Receptors and Signal Transduction ◽

10.3109/10799899709039155 ◽

1997 ◽

Vol 17 (4) ◽

pp. 647-666 ◽

Cited By ~ 7

Author(s):

B. O. Saeed ◽

D. R. Weightman ◽

C. H. Self

Keyword(s):

Human Placenta ◽

Binding Sites ◽

Corticotropin Releasing Hormone ◽

Hormone Binding ◽

Releasing Hormone

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Characterization of gonadotropin-releasing hormone (GnRH) receptors in the ovary of common carp (Cyprinus carpio)

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y92-033 ◽

1992 ◽

Vol 70 (2) ◽

pp. 268-274 ◽

Cited By ~ 15

Author(s):

Debananda Pati ◽

Hamid R. Habibi

Keyword(s):

Common Carp ◽

Cyprinus Carpio ◽

Binding Sites ◽

Tissue Concentration ◽

Gonadotropin Releasing Hormone ◽

Scatchard Analysis ◽

Single Class ◽

Releasing Hormone ◽

Carp Cyprinus Carpio

Gonadotropin-releasing hormone (GnRH) binding sites have been characterized in the fully mature common carp ovary, using an analog of salmon GnRH ([D-Arg6,Trp7,Leu8,Pro9-NEt]-GnRH; sGnRH-A) as a labeled ligand. Binding of sGnRH-A to carp follicular membrane preparation was found to be time-, temperature-, and pH-dependent. Optimal binding was achieved after 40 min of incubation at 4 °C at pH 7.6; binding was found to be unstable at room temperature. Binding of radioligand was a function of tissue concentration, with a linear correlation over the range of 8.0–40.0 μg membrane protein per tube. Incubation of membrane preparations with increasing levels of [125I]sGnRH-A revealed saturable binding at radioligand concentrations greater than 400 nM. The binding of [125I]sGnRH-A to the carp ovary was also found to be reversible; addition of unlabeled sGnRH-A (10−6 M) after reaching equilibrium resulted in complete dissociation of [125I]sGnRH-A within 30 min, and the log dissociation plot indicated the existence of a single class of binding sites. Addition of unlabeled sGnRH-A displaced the bound [125I]sGnRH-A in a dose-related manner. Hill plot as well as Scatchard analysis suggested the presence of one class of high affinity GnRH binding sites. Bound [125I]sGnRH-A was also found to be displaceable by other GnRH peptides, including sGnRH ([Trp7,Leu8]-GnRH), cGnRH-II ([His5,Trp7,Tyr8]-GnRH) and a GnRH antagonist ([D-pGlu1,D-Phe2,D-Trp3,6]-GnRH; GnRH-ANT) in a parallel fashion, indicating that these peptides bind to the same class of binding sites. sGnRH-A and cGnRH-II were found to bind with greater affinities than sGnRH and GnRH-ANT to the carp ovarian binding sites. These results provide for the first time characterization of GnRH binding sites in the ovary of a teleost species, Cyprinus carpio.Key words: gonadotropin-releasing hormone, luteinizing hormone releasing hormone, receptor, ovary, carp, Cyprinus carpio.

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Identification and characterization of [125I]endothelin binding sites on stem villi vessels from human placenta

European Journal of Pharmacology ◽

10.1016/0014-2999(90)92118-3 ◽

1990 ◽

Vol 183 (5) ◽

pp. 1800

Author(s):

C. Robaut ◽

F. Mondon ◽

F. Ferré ◽

I. Cavero

Keyword(s):

Human Placenta ◽

Binding Sites ◽

Identification And Characterization ◽

Stem Villi

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Solubilization and characterization of the rat pituitary gonadotrophin-releasing hormone receptor

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0010187 ◽

1988 ◽

Vol 1 (3) ◽

pp. 187-196 ◽

Cited By ~ 3

Author(s):

M. Iwashita ◽

K. Hirota ◽

S.-I. Izumi ◽

H.-C. Chen ◽

K.J. Catt

Keyword(s):

Hormone Receptor ◽

Releasing Hormone ◽

Rat Pituitary ◽

Gonadotrophin Releasing Hormone

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Characterization of Thromboxane A2/Prostaglandin H2 Receptors in Porcine Coronary Artery -The Inhibitory Effect of a Novel Dibenzoxepin Derivative, KW-3635

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648498 ◽

1992 ◽

Vol 67 (05) ◽

pp. 582-584 ◽

Cited By ~ 2

Author(s):

Ichiro Miki ◽

Akio Ishii

Keyword(s):

Coronary Artery ◽

Binding Sites ◽

Thromboxane A2 ◽

Inhibitory Effect ◽

Scatchard Analysis ◽

Single Class ◽

Porcine Coronary Artery ◽

Equilibrium Binding ◽

H2 Receptors

SummaryWe characterized the thromboxane A2/prostaglandin H2 receptors in porcine coronary artery. The binding of [3H]SQ 29,548, a thromboxane A2 antagonist, to coronary arterial membranes was saturable and displaceable. Scatchard analysis of equilibrium binding showed a single class of high affinity binding sites with a dissociation constant of 18.5 ±1.0 nM and the maximum binding of 80.7 ± 5.2 fmol/mg protein. [3H]SQ 29,548 binding was concentration-dependently inhibited by thromboxane A2 antagonists such as SQ 29,548, BM13505 and BM13177 or the thromboxane A2 agonists such as U46619 and U44069. KW-3635, a novel dibenzoxepin derivative, concentration-dependently inhibited the [3H]SQ 29,548 binding to thromboxane A2/prosta-glandin H2 receptors in coronary artery with an inhibition constant of 6.0 ± 0.69 nM (mean ± S.E.M.).

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