Effects of alpha-difluoromethylornithine, a specific irreversible inhibitor of ornithine decarboxylase, on nucleic acids and proteins in developing rat brain: critical perinatal periods for regional selectivity.

Published

Journal Article

Ornithine decarboxylase and its metabolic products, the polyamines, are known to coordinate macromolecule synthesis in developing neural tissues; consequently, inhibition of this enzyme by alpha-difluoromethylornithine interferes with cellular replication and differentiation. We examined the regional selectivity of the effect of alpha-difluoromethylornithine administered either postnatally (days 1-19) or during gestation (days 15-17), in order to determine whether specific phases of maturation are particularly sensitive to polyamine depletion. In the cerebellum, which undergoes major phases of replication and differentiation after birth, postnatal alpha-difluoromethylornithine administration caused a profound and progressive deficit in tissue weight gain as well as in DNA, RNA and protein content. Although regions which develop earlier (cerebral cortex, midbrain + brain stem) also showed adverse effects of postnatal alpha-difluoromethylornithine, the deficits were of much smaller magnitude and were comparable to the effect of the drug on general body growth. Despite these regional differences, inhibition of DNA synthesis ([3H]thymidine incorporation) was similar in cerebellum and in midbrain + brain stem, indicating that the direct impact of alpha-difluoromethylornithine-induced polyamine depletion is exerted in both; DNA synthesis in cerebral cortex was spared relative to the other two regions. These data suggested that the impact of alpha-difluoromethylornithine on development depends, in part, upon the relative degree of maturation of each brain region at the time of drug exposure. In confirmation of this hypothesis, prenatal alpha-difluoromethylornithine given on gestational days 15-17 resulted in loss of the specificity toward cerebellar development and enhancement of effects on cerebral cortex, the region which had displayed the least sensitivity to postnatal alpha-difluoromethylornithine.

Full Text

Duke Authors

Cited Authors

  • Bell, JM; Whitmore, WL; Slotkin, TA

Published Date

  • February 1, 1986

Published In

Volume / Issue

  • 17 / 2

Start / End Page

  • 399 - 407

PubMed ID

  • 2422585

Pubmed Central ID

  • 2422585

Electronic International Standard Serial Number (EISSN)

  • 1873-7544

International Standard Serial Number (ISSN)

  • 0306-4522

Digital Object Identifier (DOI)

  • 10.1016/0306-4522(86)90255-1

Language

  • eng