title: Sex differences in the control of plasma concentrations and urinary excretion of glycine betaine in patients attending a lipid disorders clinic.
abstract: OBJECTIVE
  To find whether the control of betaine metabolism differs between male and female patients and identify the effects of insulin and other hormones.
  
  
  METHODS
  Data from non-diabetic lipid clinic patients (82 female symbol and 76 male symbol) were re-analyzed by sex. Data on insulin, thyroid hormones and leptin were included in models to identify factors affecting the circulation and excretion of betaine and its metabolites.
  
  
  RESULTS
  Different factors influenced plasma concentrations and urinary excretion of betaine, dimethylglycine and homocysteine in males and females. In males, apolipoprotein B (negative), thyroid stimulating hormone (positive) and insulin (negative) predicted circulating betaine, consistent with betaine-homocysteine methyltransferase mediated control. In females, insulin positively predicted plasma dimethylglycine. Urinary betaine excretion positively predicted circulating homocysteine in males (p<0.001), whereas dimethylglycine excretion (also indicating betaine loss) was a stronger positive predictor (p<0.001) in females. Carnitine affected betaine homeostasis.
  
  
  CONCLUSIONS
  Betaine metabolism is under endocrine control, and studies should use sex stratified groups.
authors: Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. michael.lever@chmeds.ac.nz
authors: Michael
authors: M
authors: Lever
authors: Wendy
authors: W
authors: Atkinson
authors: Peter M
authors: PM
authors: George
authors: Stephen T
authors: ST
authors: Chambers
mesh_terms: D000328:Adult; D001622:Betaine / Q000097:blood* / Q000652:urine*; D050940:Betaine-Homocysteine S-Methyltransferase / Q000378:metabolism; D002331:Carnitine / Q000097:blood / Q000652:urine; D005260:Female; D006710:Homocysteine / Q000097:blood; D006801:Humans; D052439:Lipid Metabolism Disorders / Q000097:blood* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D012521:Sarcosine / Q000031:analogs & derivatives / Q000097:blood / Q000652:urine; D012737:Sex Factors; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D013963:Thyroid Hormones; D006710:Homocysteine; D001622:Betaine; C025138:dimethylglycine; D050940:Betaine-Homocysteine S-Methyltransferase; D002331:Carnitine; D012521:Sarcosine