title: Energy allocation between brain and body during ontogenetic development.
abstract: OBJECTIVE
  We here studied how energy is allocated between brain and body both during the ontogenetic development from a child to an adult and during weight loss.
  
  
  METHODS
  We investigated 180 normal weight female and male children and adolescents (aged 6.1-19.9 years) as well as 35 overweight adolescents undergoing weight reduction intervention. 52 normal weight and 42 obese adult women were used for comparison. We assessed brain mass by magnetic-resonance-imaging and body metabolism by indirect calorimetry. To study how energy is allocated between brain and body, we measured plasma insulin, since insulin fulfils the functions of a glucose allocating hormone, i.e., peripheral glucose uptake depends on insulin, central uptake does not. We used reference data obtained in the field of comparative biology. In a brain-body-plot, we calculated the distance between each subject and a reference mammal of comparable size and named the distance "encephalic measure." With higher encephalic measures, more energy is allocated to the brain.
  
  
  RESULTS
  We found that ontogenetic development from a child to an adult was indicated by decreasing encephalic measures in females (r = -0.729, P < 0.001) and increasing plasma insulin concentrations (F = 6.6, P = 0.002 in females and F = 8.6, P < 0.001 in males). Weight loss of about 5 kg in females and about 9 kg in males resulted in reduced insulin concentrations and increased encephalic measures.
  
  
  CONCLUSIONS
  Our results indicate that the share of energy allocated to the brain increased with weight loss, but decreased during the ontogenetic development from childhood to adolescence. These developmental changes in brain-to-body energy allocation appear to be driven by increasing plasma insulin concentrations.
authors.affiliation: Medical Clinic 1, University of Luebeck, Ratzeburger Allee 160, 23538, Luebeck, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Kubera
authors.forename: Anja
authors.initials: A
authors.lastname: Bosy-Westphal
authors.forename: Achim
authors.initials: A
authors.lastname: Peters
authors.forename: Wiebke
authors.initials: W
authors.lastname: Braun
authors.forename: Dirk
authors.initials: D
authors.lastname: Langemann
authors.forename: Stephanie
authors.initials: S
authors.lastname: Neugebohren
authors.forename: Martin
authors.initials: M
authors.lastname: Heller
authors.forename: Manfred James
authors.initials: MJ
authors.lastname: Müller
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002153:Calorimetry, Indirect; D002648:Child; D002657:Child Development; D004734:Energy Metabolism; D005260:Female; D005858:Germany; D006801:Humans; D007328:Insulin / Q000097:blood*; D008279:Magnetic Resonance Imaging; D008297:Male; D050177:Overweight / Q000378:metabolism; D055815:Young Adult
chemical_list: D007328:Insulin