Desensitization and internalization of human and xenopus gonadotropin-releasing hormone receptors expressed in alphaT4 pituitary cells using recombinant adenovirus

J N Hislop, M T Madziva, H M Everest, T Harding, J B Uney, G B Willars, R P Millar, B E Troskie, J S Davidson, C A McArdle

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Nonmammalian vertebrates express at least two forms of GnRH and distinct forms of GnRH receptor (GnRH-R) have coevolved with their ligands. Mammalian and nonmammalian GnRH-R have key structural differences (notably the lack of C-terminal tails in mammalian GnRH-R) and comparative studies are beginning to reveal their functional relevance. However, cellular context and receptor density influence G protein-coupled receptor function and may be important variables in such work using heterologous expression systems. Here we report a comparative study using alphaT4 cells (gonadotrope progenitors that lack endogenous GnRH-R) transfected with a mammalian (human) or nonmammalian (Xenopus laevis type I) GnRH-R. Because conventional transfection strategies proved inefficient, recombinant adenovirus expressing these receptors were constructed, enabling controlled and efficient GnRH-R expression. When expressed in alphaT4 cells at physiological density, these GnRH-Rs retain the pharmacology of their endogenous counterparts (as judged by ligand specificity in radioligand binding and inositol phosphate accumulation assays) but do not activate adenylyl cyclase and are not constitutively active. Moreover, the Xenopus GnRH-R rapidly desensitizes and internalizes in these cells, whereas the human GnRH-R does not, and the internalization rates are not dependent upon receptor number. These data extend studies in COS, HEK, and GH3 cells showing that other GnRH-R with C-terminal tails desensitize and internalize rapidly, whereas tail-less mammalian GnRH-R do not. Retention of these distinctions at physiological receptor density in gonadotrope lineage cells, supports the argument that the evolution of nondesensitizing mammalian GnRH-Rs is functionally relevant and related to the development of mammalian reproductive strategies.
Original languageEnglish
Pages (from-to)4564-75
Number of pages12
JournalEndocrinology
Volume141
Issue number12
DOIs
Publication statusPublished - Dec 2000

Fingerprint

LHRH Receptors
Xenopus
Adenoviridae
Gonadotropin-Releasing Hormone
Tail
Ligands
human GNRHR protein
Inositol Phosphates
Xenopus laevis
G-Protein-Coupled Receptors
Adenylyl Cyclases
Transfection
Vertebrates
Stem Cells
Pharmacology

Keywords

  • Adenoviridae
  • Adenylate Cyclase
  • Animals
  • Binding, Competitive
  • Buserelin
  • Cell Line
  • Enzyme Activation
  • Gene Expression
  • Gonadotropin-Releasing Hormone
  • Humans
  • Inositol 1,4,5-Trisphosphate
  • Inositol Phosphates
  • Iodine Radioisotopes
  • Kinetics
  • Pituitary Gland
  • Receptors, LHRH
  • Recombinant Proteins
  • Stem Cells
  • Transfection
  • Xenopus laevis

Cite this

Desensitization and internalization of human and xenopus gonadotropin-releasing hormone receptors expressed in alphaT4 pituitary cells using recombinant adenovirus. / Hislop, J N; Madziva, M T; Everest, H M; Harding, T; Uney, J B; Willars, G B; Millar, R P; Troskie, B E; Davidson, J S; McArdle, C A.

In: Endocrinology, Vol. 141, No. 12, 12.2000, p. 4564-75.

Research output: Contribution to journalArticle

Hislop, JN, Madziva, MT, Everest, HM, Harding, T, Uney, JB, Willars, GB, Millar, RP, Troskie, BE, Davidson, JS & McArdle, CA 2000, 'Desensitization and internalization of human and xenopus gonadotropin-releasing hormone receptors expressed in alphaT4 pituitary cells using recombinant adenovirus', Endocrinology, vol. 141, no. 12, pp. 4564-75. https://doi.org/10.1210/endo.141.12.7813
Hislop, J N ; Madziva, M T ; Everest, H M ; Harding, T ; Uney, J B ; Willars, G B ; Millar, R P ; Troskie, B E ; Davidson, J S ; McArdle, C A. / Desensitization and internalization of human and xenopus gonadotropin-releasing hormone receptors expressed in alphaT4 pituitary cells using recombinant adenovirus. In: Endocrinology. 2000 ; Vol. 141, No. 12. pp. 4564-75.
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AU - Hislop, J N

AU - Madziva, M T

AU - Everest, H M

AU - Harding, T

AU - Uney, J B

AU - Willars, G B

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AU - Troskie, B E

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KW - Pituitary Gland

KW - Receptors, LHRH

KW - Recombinant Proteins

KW - Stem Cells

KW - Transfection

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