Prenatal exposure to a low-protein diet programs disordered regulation of lipid metabolism in the aging rat

Am J Physiol Endocrinol Metab. 2007 Jun;292(6):E1702-14. doi: 10.1152/ajpendo.00605.2006. Epub 2007 Feb 13.

Abstract

The nutritional environment encountered during fetal life is strongly implicated as a determinant of lifelong metabolic capacity and risk of disease. Pregnant rats were fed a control or low-protein (LP) diet, targeted to early (LPE), mid-(LPM), or late (LPL) pregnancy, or throughout gestation (LPA). The offspring were studied at 1, 9, and 18 mo of age. All LP-exposed groups had similar plasma triglyceride, cholesterol, glucose, and insulin concentrations to those of controls at 1 and 9 mo of age, but by 18 mo there was evidence of LP-programmed hypertriglyceridemia and insulin resistance. All LP-exposed groups exhibited histological evidence of hepatic steatosis and were found to have two- to threefold more hepatic triglyceride than control animals. These phenotypic changes were accompanied by age-related changes in mRNA and protein expression of the transcription factors SREBP-1c, ChREBP, PPARgamma, and PPARalpha and their respective downstream target genes ACC1, FAS, L-PK, and MCAD. At 9 mo of age, the LP groups exhibited suppression of the SREBP-1c-related lipogenic pathway but between 9 and 18 mo underwent a switch to increased lipogenic capacity with a lower expression of PPARgamma and MCAD, consistent with reduced lipid oxidation. The findings indicate that prenatal protein restriction programs development of a metabolic syndrome-like phenotype that develops only with senescence. The data implicate altered expression of SREBP-1c and ChREBP as key mediators of the programmed phenotype, but the basis of the switch in metabolic status that occurred between 9 and 18 mo of age is, as yet, unidentified.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism
  • Aging / blood
  • Aging / metabolism*
  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • Body Weight
  • Diet, Protein-Restricted*
  • Fatty Liver / etiology
  • Female
  • Hypertriglyceridemia / etiology
  • Insulin Resistance
  • Lipid Metabolism*
  • Liver / anatomy & histology
  • Liver / metabolism
  • Muscle, Skeletal / metabolism
  • Organ Size
  • PPAR alpha / genetics
  • PPAR alpha / metabolism
  • PPAR gamma / genetics
  • PPAR gamma / metabolism
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism
  • Time Factors
  • Triglycerides / metabolism

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Mlxipl protein, rat
  • PPAR alpha
  • PPAR gamma
  • RNA, Messenger
  • Sterol Regulatory Element Binding Protein 1
  • Triglycerides