title: Production of congenital limb defects with retinoic acid: phenomenological evidence of progressive differentiation during limb morphogenesis.
abstract: Maternal administration of a single dose of retinoic acid (vitamin A acid, 100 mg/kg) on either the 11th, 11 1/2, 12th, 12 1/2, 13th or 13 1/2 day of gestation produced phocomelia or partial phocomelia in ICR/DUB fetuses. The results depended upon the time of treatment and two gradients of effect were produced: 1) cranio-caudal gradient, since forelimb defects resulted from between days 11 and 13, while similar hindlimb abnormalities were produced by administration of retinoic acid 12 to 24 hours later: 2) proximo-distal gradient, due to the heterogenous sensitivity among individual bones of the limb. In the forelimb, early treatment (11th day) produced humero-unlar defects and later treatment (12th day) ulnoradial defects. A similar proximo-distal gradient was observed in the hindlimb. The use of teratological studies as a tool to assist morphogenetic investigation is discussed.
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000209:etiology*; D000818:Animals; D004480:Ectromelia / Q000139:chemically induced; D005260:Female; D005552:Forelimb / Q000002:abnormalities; D006614:Hindlimb / Q000002:abnormalities; D006801:Humans; D017880:Limb Deformities, Congenital; D051379:Mice; D008813:Mice, Inbred ICR; D011247:Pregnancy; D011270:Pregnancy, Animal; D013997:Time Factors; D014212:Tretinoin / Q000506:poisoning*
chemical_list: D014212:Tretinoin