The sexual maturation occurred by the changes of steroid hormones was known to sex-dependently and/or agedependently regulate the lipid metabolism in various animal species. Our current study demonstrates that lipid and its functional fatty acids can be changed depending on the status of sexual maturation. Of the functional fatty acids, γ- linolenic acid (GLA; 18:3n-6) is an important factor for maintaining human health. The purpose of our study was to investigate the level of GLA in mice with different stages of sexual maturation. To this end, the longissimus muscle (LM) of immature (3-week-old) and mature (7-week-old) female mice was analysed for the fatty acid composition by gas chromatography. Furthermore, both gene and protein level of Δ6 desaturase (FADS2) which is involved in GLA metabolism by real time PCR and Western blotting, respectively. Mature females showed greater (P<0.05) serum 17β -estradiol (E2) level and LM GLA contents than immature group. The mRNA and protein levels of FADS2, which converts precursor linoleic acid into GLA, were higher (P<0.05) in mature female mice than in immature mice. In conclusion, these results show that sexual maturation of female mice induces GLA and FADS2 contents in LM.

INTRODUCTION
 MATERIALS AND METHODS
  1. Animals
  2. Reagents
  3. Preparation of Samples
  4. Electrochemiluminescence Immunoassay
  5. Gas Chromatography
  6. Real-Time PCR
  7. Western Blot Analysis
  8. Statistical Analysis
 RESULTS
  1. Effect of Sexual Maturation on the Levels of Testosterone and 17β-Estradiol in Female Mice
  2. Effect of Sexual Maturation on the Levels of n-6 PUFA in theMuscle Tissue of Female mice
  3. Effect of Sexual Maturation on Expression of FADS2 Gene relatedto GLA Metabolism in Female Mice
  4. Effect of Sexual Maturation on Level of FADS2 Protein for GLAMetabolism in the Female Mice
 DISCUSSION
 REFERENCES

• Chang Seok Park(Hanwoo Research Institute, National Institute of Animal Science, RDA, Pyeongchang 232-950, Korea)
• Sang-Rae Cho(Hanwoo Research Institute, National Institute of Animal Science, RDA, Pyeongchang 232-950, Korea)
• Young Sik Park(Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 742-711, Korea) Correspondence