title: Regulation of supply and demand for maternal nutrients in mammals by imprinted genes.
abstract: The placenta has evolved in eutherian mammals primarily to provide nutrients for the developing fetus. The genetic control of the regulation of supply and demand for maternal nutrients is not understood. In this review we argue that imprinted genes have central roles in controlling both the fetal demand for, and the placental supply of, maternal nutrients. Recent studies on Igf2 (insulin-like growth factor 2) knockout mouse models provide experimental support for this hypothesis. These show effects on placental transport capacity consistent with a role of IGF-II in modulating both the placental supply and fetal demand for nutrients. Imprinting of genes with such functions may have coevolved with the placenta and new evidence suggests that transporter proteins, as well as the regulators themselves, may also be imprinted. These data and hypotheses are important, as deregulation of supply and demand affects fetal growth and has long term consequences for health in mammals both in the neonatal period and, as a result of fetal programming, in adulthood.
authors.affiliation: Laboratory of Developmental Genetics and Imprinting, Developmental Genetics Programme, The Babraham Institute, Cambridge CB2 4AT, UK. wol.reik@bbsrc.ac.uk
authors.forename: Wolf
authors.initials: W
authors.lastname: Reik
authors.forename: Miguel
authors.initials: M
authors.lastname: Constância
authors.forename: Abigail
authors.initials: A
authors.lastname: Fowden
authors.forename: Neil
authors.initials: N
authors.lastname: Anderson
authors.forename: Wendy
authors.initials: W
authors.lastname: Dean
authors.forename: Anne
authors.initials: A
authors.lastname: Ferguson-Smith
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tycko
authors.forename: Colin
authors.initials: C
authors.lastname: Sibley
mesh_terms: D000818:Animals; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000502:physiology; D018392:Genomic Imprinting / Q000502:physiology*; D006801:Humans; D008322:Mammals; D008431:Maternal-Fetal Exchange / Q000235:genetics*; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D039401:Prenatal Nutritional Physiological Phenomena / Q000502:physiology*