Estradiol control of expression and levels of estradiol-binding proteins in the medial preoptic area, medial hypothalamus and pituitary

Guang Gao, Zsöfia Herbert, Jing Kong, Nathan Gabrielson, Alan Mautz, Dongming Wu, Gustav F. Jirikowski, Jack D. Caldwell

Research output: Contribution to journalArticlepeer-review

Abstract

The brains of mammals have at least three estradiol-binding proteins: estradiol receptor-α (ERα), ERβ, and sex hormone-binding globulin (SHBG). In this study we compare the effects of estradiol treatment on the expression of mRNA for these three estradiol-binding proteins in two reproductively important brain areas, the medial preoptic area-anterior hypothalamus (MPOA-AH) and medial hypothalamus (MH) as well as in the hippocampus in ovariectomized rats, using the reverse transcriptase-polymerase chain reaction (RT-PCR). We also used surface-enhanced laser desorption ionization time of flight (SELDI-TOF) mass spectrometry (MS) to analyze the effects of estradiol in ovariectomized rats on SHBG levels in the MPOA-MH as well as the neurohypophysis. In vivo estradiol treatment in ovariectomized rats eliminated or significantly reduced expression of all three estradiol-binding proteins in both the MPOA-AH and MH. This change in ERα, ERβ, and SHBG expression did not occur in the hippocampus. Both Northern blot and DNA sequence analysis confirmed the results of the RT-PCR for SHBG. SELDI-TOF MS analysis demonstrated that in vivo estradiol treatments resulted in dramatically decreased levels of SHBG in the hypothalamus and that a reduction in SHBG mRNA by estradiol treatment also resulted in a reduction in SHBG protein levels. Estradiol treatment also eliminated detectable SHBG from the neurohypophysis, suggesting that estradiol controls SHBG levels in this release site. That in vivo estradiol treatments had the same inhibitory effects on mRNA levels for SHBG and both ERs suggests similar translational control mechanisms for all three steroid-binding proteins in the brain. That estradiol treatments also reduced pituitary SHBG suggests that such treatment releases SHBG from the neurohypophysis.

Original languageEnglish (US)
Pages (from-to)61-71
Number of pages11
JournalNeuroendocrinology
Volume78
Issue number2
DOIs
StatePublished - Oct 9 2003
Externally publishedYes

Keywords

  • Estradiol-binding protein
  • Gonadal steroid receptors
  • Gonadal steroids
  • Hippocampus
  • Medial hypothalamus
  • Molecular neuroendocrinology
  • Neurohypophysis
  • Paraventricular nucleus
  • Preoptic area
  • Sex hormone-binding globulin

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Cellular and Molecular Neuroscience

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