Cranial effects of retinoic acid in the loop-tail (Lp) mutant mouse.
The effects of retinoic acid (RA) on the manifestation and nature of neural tube defects (NTD) in heterozygous embryos of mutant mice carrying the gene loop-tail (Lp) and in normal (+/+) littermates and embryos from normal homozygous matings were compared with NTD that occur in untreated abnormal homozygous (Lp/Lp) embryos. A single intraperitoneal dose (5 mg/kg) of RA administered at 9 AM or 3 PM on day 8 of gestation induced NTD in +/+ as well as Lp/+ embryos removed on day 12 of gestation. All of the NTD were confined to the brain and consisted of exencephaly involving the diencephalon, mesencephalon, and metencephalon. In neither phenotype (Lp/+; +/+) was the massive exencephaly and myeloschisis characteristic of untreated Lp/Lp embryos produced; thus, it is possible that the teratogenic mechanisms of RA-induced defects and of Lp-induced defects may differ.
Wilson
D B
DB
Division of Anatomy, School of Medicine, University of California, San Diego, La Jolla 92093.
Wyatt
D P
DP
Gookin
J L
JL
D000818:Animals; D004027:Diencephalon / Q000166:cytology / Q000187:drug effects; D005260:Female; D005313:Fetal Death / Q000139:chemically induced; D007274:Injections, Intraperitoneal; D008431:Maternal-Fetal Exchange; D051379:Mice; D008817:Mice, Mutant Strains / Q000196:embryology; D009436:Neural Tube Defects / Q000139:chemically induced*; D011247:Pregnancy; D014212:Tretinoin / Q000633:toxicity*
D014212:Tretinoin