title: Effect of propylthiouracil treatment during prenatal and early postnatal development on the neocortex of rat pups.
abstract: The effects of a pre- and postnatal hypothyroid environment on the development of the neocortex have been determined. Rats were treated with propylthiouracil (PTU) with or without thyroid hormone supplementation during pregnancy and throughout the early development of the pups. The Cavalieri method was used to provide an estimate of the volume of the neocortex, and a combination of the Cavalieri method and the 'disector' particle-counting method provided an unbiased estimate of the numbers of glia and neurons in the neocortex. In pups from non-treated rats the mean volume of the neocortex increased from 31.3 mm3 at 5 days postnatally to 191.5 mm3 at 20 days and then remained constant to day 48. Similarly, the mean number of glial cells increased from 5.2 x 10(6) at day 5 to 12.0 x 10(6) on day 20 and then remained constant to day 48. The mean number of neurons in the neocortex in the control condition was constant at about 14.6 x 10(6) from day 5 to day 48. PTU treatment during pregnancy and postnatal development significantly decreased the mean volume of the neocortex at all of the stages studied, for example from 31.3 to 23.3 mm3 (p less than 0.001) on day 5 and from 191.5 to 155.0 mm3 (p less than 0.001) on day 20. Supplementation with thyroxine (T4) or tri-iodothyronine partially reversed this at certain stages. For example, the mean volume of the neocortex at 48 days was 197.5 mm3 in control rats, 118.1 mm3 in PTU-treated rats and 169.3 mm3 in PTU-treated rats supplemented with T4. Within the neocortex, the volume of the neuropile was more severely affected than was the volume of the neuron cell bodies.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Human Anatomy and Cell Biology, University of Liverpool, UK.
authors.forename: M
authors.initials: M
authors.lastname: Behnam-Rassoli
authors.forename: L C
authors.initials: LC
authors.lastname: Herbert
authors.forename: V
authors.initials: V
authors.lastname: Howard
authors.forename: P O
authors.initials: PO
authors.lastname: Pharoah
authors.forename: M
authors.initials: M
authors.lastname: Stanisstreet
mesh_terms: D000818:Animals; D002452:Cell Count; D002540:Cerebral Cortex / Q000187:drug effects / Q000196:embryology* / Q000254:growth & development; D005260:Female; D008098:Litter Size / Q000187:drug effects; D008431:Maternal-Fetal Exchange; D009457:Neuroglia / Q000166:cytology; D009474:Neurons / Q000166:cytology; D011247:Pregnancy; D011441:Propylthiouracil / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D014284:Triiodothyronine; D011441:Propylthiouracil; D013974:Thyroxine