Dietary gamma-linolenic acid in the form of borage oil causes less body fat accumulation accompanying an increase in uncoupling protein 1 mRNA level in brown adipose tissue

Comp Biochem Physiol B Biochem Mol Biol. 2000 Oct;127(2):213-22. doi: 10.1016/s0305-0491(00)00254-6.


Rats were fed a low-fat diet containing 2% safflower oil or 20% fat diets containing either safflower oil rich in linoleic acid, borage oil containing 25% gamma (gamma)-linolenic acid or enzymatically prepared gamma-linolenic acid enriched borage oil containing 47% gamma-linolenic acid for 14 days. Energy intake and growth of animals were the same among groups. A high safflower oil diet compared with a low-fat diet caused significant increases in both epididymal and perirenal white adipose tissue weights. However, high-fat diets rich in gamma-linolenic acid failed to do so. Compared with a low-fat diet, all the high-fat diets increased mRNA levels of uncoupling protein 1 and lipoprotein lipase in brown adipose tissue. The extents of the increase were greater with high-fat diets rich in gamma-linolenic acid. Various high-fat diets, compared with a low-fat diet, decreased glucose transporter 4 mRNA in white adipose tissue to the same levels. The amount and types of dietary fat did not affect the leptin mRNA level in epididymal white adipose tissue. However, a high safflower oil diet, but not high-fat diets rich in gamma-linolenic acid relative to a low-fat diet, increased perirenal white adipose tissue leptin mRNA levels. All high-fat diets, relative to a low-fat diet, increased the hepatic mitochondrial fatty acid oxidation rate and fatty acid oxidation enzyme mRNA abundances to the same levels. High-fat diets also increased these parameters in the peroxisomal pathway, and the increases were greater with high-fat diets rich in gamma-linolenic acid. The physiological activity in increasing brown adipose tissue gene expression and peroxisomal fatty acid oxidation was similar between the two types of borage oil differing in gamma-linolenic acid content. It was suggested that dietary gamma-linolenic acid attenuates body fat accumulation through the increase in gene expressions of uncoupling protein 1 in brown adipose tissue. An increase in hepatic peroxisomal fatty acid oxidation may also contribute to the physiological activity of gamma-linolenic acid in decreasing body fat mass.

MeSH terms

  • Adipose Tissue / metabolism
  • Adipose Tissue, Brown / drug effects*
  • Adipose Tissue, Brown / metabolism
  • Animals
  • Carrier Proteins / biosynthesis*
  • Diet
  • Diet, Fat-Restricted
  • Fatty Acids / metabolism
  • Ion Channels
  • Leptin / metabolism
  • Lipoprotein Lipase / metabolism
  • Liver / enzymology
  • Male
  • Membrane Proteins / biosynthesis*
  • Mitochondria / metabolism
  • Mitochondrial Proteins
  • Monosaccharide Transport Proteins / metabolism
  • Oxygen / metabolism
  • Palmitoyl Coenzyme A / metabolism
  • Peroxisomes / metabolism
  • Plant Oils / pharmacology*
  • RNA, Messenger / metabolism*
  • Rats
  • Safflower Oil / pharmacology
  • Uncoupling Protein 1
  • gamma-Linolenic Acid / pharmacology*


  • Carrier Proteins
  • Fatty Acids
  • Ion Channels
  • Leptin
  • Membrane Proteins
  • Mitochondrial Proteins
  • Monosaccharide Transport Proteins
  • Plant Oils
  • RNA, Messenger
  • Ucp1 protein, rat
  • Uncoupling Protein 1
  • Palmitoyl Coenzyme A
  • gamma-Linolenic Acid
  • Safflower Oil
  • Lipoprotein Lipase
  • borage oil
  • Oxygen