Functional characterization of the alternatively spliced, placental human growth hormone receptor

Margrit Urbanek, J. Eric Russell, Nancy E. Cooke, Stephen A. Liebhaber*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

The human growth hormone family of peptide hormones is encoded by five genes, pituitary growth hormone (hGH-N), and four placentally expressed genes, growth hormone variant (hGH-V), chorionic somatomammotropin A and B (hCS-A, hCS-B), and prolactin (hPrl). As part of an effort to define the local effects of the placentally expressed members of the GH/Prl family of hormones on the placenta, we have identified an isoform (hGHRd3) of the growth hormone receptor expressed in the placental villi. hGHRd3 mRNA differs from the liver GHR mRNA by the deletion of a 66-base pair segment encoding exon 3. In this study we show that hGHRd3 mRNA encodes a stable and functional receptor. hGHRd3 mRNA is efficiently translated and processed in a rabbit reticulocyte lysate translation system as well as in an in vivo Xenopus laevis oocyte expression system. In Xenopus oocytes hGHRd3 is stably integrated into the cell membrane and binds and internalizes ligand as efficiently as hGHR. hGHRd3 binds all three of the placentally expressed members of the GH/Prl gene family (hGH-V, hCS, and Prl) as well as both the 22 and 20 kDa isoforms of the pituitary hGH-N. The results of the present study strongly support the expression of a functional hGHRd3 isoreceptor in the placenta which may serve in autocrine, paracrine, and/or endocrine activation.

Original languageEnglish (US)
Pages (from-to)19025-19032
Number of pages8
JournalJournal of Biological Chemistry
Volume268
Issue number25
StatePublished - Jan 1 1993

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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