Fetal dexamethasone exposure alters macromolecular characteristics of rat brain development: a critical period for regionally selective alterations?

Published

Journal Article

Fetal glucocorticoid exposure retards postnatal growth and evokes abnormalities of nervous system structure and function. To examine the underlying mechanisms, we administered 0.2 or 0.8 mg/kg of dexamethasone to pregnant rats on gestational days 17, 18, and 19 and assessed brain region cell development with indices of DNA content (total cell numbers), DNA concentration (cell packing density), and protein/DNA ratio (relative cell size). Dexamethasone evoked deficits of pup body and brain region weights, but the brain regions displayed growth-sparing associated initially with preservation of cell numbers (normal or elevated DNA content and concentration), at the expense of relative cell size (decreased protein/DNA). Subsequently, brain cell acquisition lagged behind that of controls, with deficits in DNA and elevations of protein/DNA. In midbrain + brainstem and in cerebellum, cell markers returned to normal by weaning. However, the forebrain showed persistent elevations of DNA and reduced protein/DNA, indicative of replacement of neurons with glia. Because the treatment period coincided with the timing of neuronal cell replication in the forebrain, but not in the other regions, these results suggest that the critical period for lasting deficits of dexamethasone coincides with the peak of neuronal mitosis.

Full Text

Duke Authors

Cited Authors

  • Carlos, RQ; Seidler, FJ; Slotkin, TA

Published Date

  • July 1992

Published In

Volume / Issue

  • 46 / 1

Start / End Page

  • 45 - 59

PubMed ID

  • 1641811

Pubmed Central ID

  • 1641811

International Standard Serial Number (ISSN)

  • 0040-3709

Digital Object Identifier (DOI)

  • 10.1002/tera.1420460108

Language

  • eng

Conference Location

  • United States