title: Relationship of Δ(6) -desaturase and Δ(5) -desaturase activities with thyroid hormone status in adolescents with eating disorders and weight loss.
abstract: OBJECTIVE
  In starvation, there is down-regulation of metabolism and changes in essential fatty acid (FA) status, which could be related to alterations of desaturase activities. Presently, the relationship between thyroid hormones and desaturase activities has been investigated in adolescents with eating disorders and weight loss.
  
  
  METHODS
  Serum triiodothyronine concentrations and proportions of polyunsaturated FA in plasma phospholipids were analysed in blood samples from 227 adolescents with ED. Δ(6) -desaturase (D6D) activity was calculated as the FA ratio 20:3ω6/18:2ω6 and Δ(5) -desaturase (D5D) activity as the ratio 20:4ω6/20:3ω6.
  
  
  RESULTS
  Serum triiodothyronine concentrations were related to leanness and ongoing weight loss. The estimated D6D activity was positively correlated with serum triiodothyronine (R(2) = 0.232; p < 0.001). D5D activity exhibited a strong inverse correlation with serum triiodothyronine (R(2) = 0.410; p < 0.001).
  
  
  CONCLUSIONS
  Changes in desaturase activities during starvation cannot be explained by inhibition/disinhibition by essential FA only. It is possible that the effects of starvation on these enzyme activities, and hence on essential FA status, are mediated by triiodothyronine.
authors: Dept of Women's and Children's Health, Uppsala University, Uppsala, Sweden. ingemar.swenne@akademiska.se
authors: Ingemar
authors: I
authors: Swenne
authors: Bengt
authors: B
authors: Vessby
mesh_terms: D000293:Adolescent; D000090943:Delta-5 Fatty Acid Desaturase; D044943:Fatty Acid Desaturases / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D001068:Feeding and Eating Disorders / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D050602:Linoleoyl-CoA Desaturase / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D013548:Sweden; D014284:Triiodothyronine / Q000097:blood*; D015431:Weight Loss / Q000502:physiology*
chemical_list: D000090943:Delta-5 Fatty Acid Desaturase; D014284:Triiodothyronine; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase
keywords: Desaturase; Eating disorder; PUFA; Triiodothyronine