title: The heritability of beta cell function parameters in a mixed meal test design.
abstract: OBJECTIVE
  We estimated the heritability of individual differences in beta cell function after a mixed meal test designed to assess a wide range of classical and model-derived beta cell function parameters.
  
  
  METHODS
  A total of 183 healthy participants (77 men), recruited from the Netherlands Twin Register, took part in a 4 h protocol, which included a mixed meal test. Participants were Dutch twin pairs and their siblings, aged 20 to 49 years. All members within a family were of the same sex. Insulin sensitivity, insulinogenic index, insulin response and postprandial glycaemia were assessed, as well as model-derived parameters of beta cell function, in particular beta cell glucose sensitivity and insulin secretion rates. Genetic modelling provided the heritability of all traits. Multivariate genetic analyses were performed to test for overlap in the genetic factors influencing beta cell function, waist circumference and insulin sensitivity.
  
  
  RESULTS
  Significant heritabilities were found for insulinogenic index (63%), beta cell glucose sensitivity (50%), insulin secretion during the first 2 h postprandial (42-47%) and postprandial glycaemia (43-52%). Genetic factors influencing beta cell glucose sensitivity and insulin secretion during the first 30 postprandial min showed only negligible overlap with the genetic factors that influence waist circumference and insulin sensitivity.
  
  
  CONCLUSIONS
  The highest heritability for postprandial beta cell function was found for the insulinogenic index, but the most specific indices of heritability of beta cell function appeared to be beta cell glucose sensitivity and the insulin secretion rate during the first 30 min after a mixed meal.
authors.affiliation: Diabetes Center, VU University Medical Center, ZH 4A62, PO Box 7057, 1007 MB, Amsterdam, the Netherlands. amc.simonis-bik@vumc.nl
authors.forename: A M C
authors.initials: AM
authors.lastname: Simonis-Bik
authors.forename: D I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: J M
authors.initials: JM
authors.lastname: Dekker
authors.forename: M
authors.initials: M
authors.lastname: Diamant
authors.forename: E J C
authors.initials: EJ
authors.lastname: de Geus
authors.forename: L M
authors.initials: LM
authors.lastname: 't Hart
authors.forename: R J
authors.initials: RJ
authors.lastname: Heine
authors.forename: M H H
authors.initials: MH
authors.lastname: Kramer
authors.forename: J A
authors.initials: JA
authors.lastname: Maassen
authors.forename: A
authors.initials: A
authors.lastname: Mari
authors.forename: A
authors.initials: A
authors.lastname: Tura
authors.forename: G
authors.initials: G
authors.lastname: Willemsen
authors.forename: E M W
authors.initials: EM
authors.lastname: Eekhoff
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D055815:Young Adult
chemical_list: D007328:Insulin