title: Effects of dietary fat subtypes on glucose homeostasis during pregnancy in rats.
abstract: BACKGROUND
  Dietary n-3 and n-6 polyunsaturated fatty acids (PUFAs) have an impact on insulin secretion and sensitivity but whether and how these may be related to maternal glucose homeostasis during pregnancy is unclear.
  
  
  METHODS
  Female Wistar rats (240-250 g) were assigned to laboratory CHOW or high fat diets rich in either n-6 (safflower oil; n-6 group) or n-6 + n-3 (safflower oil + fish oil; n-3 group) PUFAs. After 10 days half of the animals in each diet group were inseminated and confirmed pregnant. An overnight fasted intravenous glucose tolerance test (500 mg glucose/kg body weight) was performed on chronically cannulated non-pregnant and 20-day pregnant rats. Indices of insulin secretion (β) and insulin sensitivity (S) were calculated from the plasma glucose and insulin responses. The fatty acid composition of phospholipids was determined in samples of liver and two skeletal muscles (soleus and red quadriceps).
  
  
  RESULTS
  Pregnancy in the CHOW group significantly increased β (P < 0.001) and decreased S (P < 0.01). In contrast, both n-6 and n-3 diets abolished both the pregnancy-induced decrease in S and pregnancy-induced increase in β with the n-3 diet having a more potent effect on both S and β. S was positively correlated with the sum of n-3 fatty acids, with docosahexaenoic acid (22:6 n-3) the major contributor, in liver (r = 0.485; P < 0.001), red quadriceps (r = 0.421; P = 0.004) and soleus (r = 0.476; P < 0.001). In contrast S was inversely related to arachidonic acid (20:4n-6) levels in liver and red quadriceps across all groups and these relationships were particularly powerful in pregnancy (liver: r = -0.785; red quadriceps: r = -0.754, both P < 0.0001).
  
  
  CONCLUSIONS
  The results demonstrate potent effects of dietary fat amount and profile on glucoregulation during pregnancy and emphasize the importance of the balance between dietary n-3 and n-6 PUFAs.
authors: Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders and Charles Perkins Centre, University of Sydney, Sydney, NSW 2006 Australia ; Metabolic Research Centre, University of Wollongong, Wollongong, NSW 2522 Australia.
authors: Len H
authors: LH
authors: Storlien
authors: Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders and Charles Perkins Centre, University of Sydney, Sydney, NSW 2006 Australia.
authors: Yan Y
authors: YY
authors: Lam
authors: Metabolic Research Centre, University of Wollongong, Wollongong, NSW 2522 Australia.
authors: Ben J
authors: BJ
authors: Wu
authors: School of Medicine, Smart Foods Centre, Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522 Australia.
authors: Linda C
authors: LC
authors: Tapsell
authors: Metabolic Research Centre, University of Wollongong, Wollongong, NSW 2522 Australia.
authors: Arthur B
authors: AB
authors: Jenkins
keywords: Dietary fat; Hyperinsulinemia; Insulin sensitivity; Pregnancy