Cell and Tissue Research

, Volume 322, Issue 2, pp 269–277

Induction of GH, PRL, and TSHβ mRNA by transfection of Pit-1 in a human pituitary adenoma-derived cell line

  • Shunsuke Miyai
  • Shinichi Yoshimura
  • Yasumasa Iwasaki
  • Susumu Takekoshi
  • Ricardo V. Lloyd
  • Robert Yoshiyuki Osamura
Regular Article

Abstract

The functional development of pituitary cells depends on the expression of a combination of transcription factors and co-factors. Pituitary-specific transcription factor-1 (Pit-1) is required for the expression of growth hormone (GH), prolactin (PRL), and the thyroid-stimulating hormone β subunit (TSHβ) and acts synergistically with the estrogen receptor (ER) and GATA-binding protein 2 (GATA-2) to induce PRL and TSHβ expression, respectively. The glycoprotein hormone α subunit (αSU) is the first hormone to be expressed during pituitary development. In addition to being expressed in follicle-stimulating hormone, luteinizing hormone (LH), and TSH cells, αSU is reported to co-localize with GH in pituitary cells. These findings have led to the suggestion that the expression of Pit-1 in cells of the αSU-based gonadotropin cell lineage might also lead to the expression of GH. In this study, we transfected HP75 cells (derived from a human non-functioning pituitary adenoma that expressed αSU and LHβ) with Pit-1 by using an adenovirus FLAG-Pit-1 construct. Most of the transfected cells expressed GH mRNA, with fewer cells expressing PRL and TSHβ mRNA. The HP75 cells expressed the genes for ER and GATA-2, thus allowing their expression of GH, PRL, and TSHβ mRNA in response to Pit-1. These results support the hypothesis that GH can be induced in cells that possess an active αSU gene and shed light on the basic molecular mechanism that drives the development of GH, PRL, and TSHβ expression in the αSU-based gonadotroph lineage.

Keywords

Pituitary adenomas Differentiation Pit-1 Glycoprotein α subunit Transcription factor Human 

Abbreviations

αSU

glycoprotein hormone alpha subunit

GH

growth hormone

PRL

prolactin

TSH

thyroid-stimulating hormone

POMC

pro-opiomelanocortin

ACTH

adrenocorticotropic hormone

FSH

follicle-stimulating hormone

LH

luteinizing hormone

Pit-1

pituitary-specific transcription factor-1

ER

estrogen receptor

Tpit

pituitary cell-restricted T-box factor

NeuroD1

neurogenic differentiation 1

SF-1

steroidogenic factor 1

GATA-2

GATA-binding protein 2

DAX1

dosage-sensitive sex-reversal, adrenal hypoplasia congenital, X chromosome

Ptx1

pituitary homeobox 1

LHX3

LIM homeobox protein 3

Prop-1

Prophet of Pit-1

GHRH-R

growth hormone-releasing hormone receptor

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Shunsuke Miyai
    • 1
  • Shinichi Yoshimura
    • 2
  • Yasumasa Iwasaki
    • 3
  • Susumu Takekoshi
    • 1
  • Ricardo V. Lloyd
    • 4
  • Robert Yoshiyuki Osamura
    • 1
  1. 1.Department of PathologyTokai University School of MedicineKanagawaJapan
  2. 2.Department of Molecular Life ScienceTokai University School of MedicineKanagawaJapan
  3. 3.Department of Internal MedicineKochi University School of MedicineKochiJapan
  4. 4.Department of Laboratory Medicine and PathologyMayo Clinic and Mayo FoundationRochester, MNUSA

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