Negative regulation of antioxidant enzyme gene expression inthe developing fetal ratlung by prenatal hormonal treatments

Youwei Chen, Philip L. Whitney, Lee Frank

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Prenatal administration of thyrotropin-releasing hormone (TRH) or TRH plus dexamethasone (DEX) to pregnant rats accelerates lung surfactant system development in late gestation, but paradoxically depresses the normal late gestational elevation in fetal lung antioxidant enzyme (AOE) activities (Pediatr Res 30:522, 1991). In these present studies, we tested whether both prenatal hormonal treatments act to depress normal fetal lung AOE development by negative regulation of AOE gene expression. We used solution hybridization to quantitate the concentration of AOE mRNA. Results of the developmental studies revealed significantly decreased lung mRNA concentrations of copper- zinc superoxide dismutase, manganese superoxide dismutase, catalase, and glutathione peroxidase in late gestation as a result of prenatal TRH treatment. The addition of DEX administration did not reverse the lowered expression of lung AOE genes due to TRH treatment, but instead resulted in significant additional decreases in pulmonary AOE mRNA levels at both 21 and 22 d of gestation. The tested AOE mRNA half-lives (stabilities) revealed no significant differences between controls (8.0-10.5 h) and TRH-treated (8.2- 9.5 h) and TRH-plus-DEX treatment (7.8-10.7 h) groups. These findings suggest that prenatal treatment with TRH and with TRH plus DEX acts to depress the normal late fetal lung AOE activity elevations by (direct) negative regulation of AOE gene expression, and the decreased AOE expression is likely regulated at the level of gene transcription rather than posttranscriptionally.

Original languageEnglish (US)
Pages (from-to)171-176
Number of pages6
JournalPediatric Research
Volume33
Issue number2
DOIs
StatePublished - Feb 1993

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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