title: Retinol-binding protein-4 is not strongly associated with insulin sensitivity in normal pregnancies.
abstract: OBJECTIVE
  Recently, experimental and clinical studies suggest that retinol-binding protein-4 (RBP4) may provide a link between obesity and insulin resistance. However, no previous studies have investigated the impact of circulating RBP4 on measures of insulin resistance in normal pregnant women, and the objective of this study is to measure serum RBP4 in early and late pregnancy and relate these to measures of insulin resistance and secretion controlling for changes in fat mass.
  
  
  METHODS
  Samples were obtained during oral glucose tolerance test (OGTT) from 44 normal pregnancies at weeks 14-16 and 30-32. Measures of fat mass were body mass index (BMI) and leptin while insulin sensitivity and secretion were predicted from OGTT. Leptin and RPB4 were measured by immunoassay.
  
  
  RESULTS
  Insulin sensitivity decreased during the course of pregnancy. Insulin sensitivity and secretion were best explained by BMI and circulating leptin, but not RBP4, both in early and late pregnancy. However, a marked increase in fasting RBP4 from early to late pregnancy was observed, and this change was associated with a decline in insulin sensitivity. A marked increase in RBP4 was found during OGTT at weeks 14-16 with an opposite temporal course at weeks 30-32.
  
  
  CONCLUSIONS
  The increased fat mass and insulin resistance during normal pregnancy was best explained by measures of fat mass. However, the increase in RBP4 from early to late pregnancy, associated with a decline in insulin sensitivity, potentially indicates interactions with glucose metabolism.
authors.affiliation: Section of Endocrinology, Medical Department, Rikshospiatelet Radiumhospitalet Medical Center, Rikshospitalet University Hospital and University of Oslo, N-0027 Oslo, Norway. thor.ueland@medisin.uio.no
authors.forename: T
authors.initials: T
authors.lastname: Ueland
authors.forename: T
authors.initials: T
authors.lastname: Dalsoren
authors.forename: N
authors.initials: N
authors.lastname: Voldner
authors.forename: K
authors.initials: K
authors.lastname: Godang
authors.forename: T
authors.initials: T
authors.lastname: Henriksen
authors.forename: J
authors.initials: J
authors.lastname: Bollerslev
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood; D008297:Male; D011247:Pregnancy; D011863:Radioimmunoassay; D054839:Retinol-Binding Proteins, Plasma / Q000032:analysis*
chemical_list: D007328:Insulin; D020738:Leptin; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma