Sex differences in the control of plasma concentrations and urinary excretion of glycine betaine in patients attending a lipid disorders clinic.
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.
Lever
Michael
M
Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. michael.lever@chmeds.ac.nz
Atkinson
Wendy
W
George
Peter M
PM
Chambers
Stephen T
ST
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
D013963:Thyroid Hormones; D006710:Homocysteine; D001622:Betaine; C025138:dimethylglycine; D050940:Betaine-Homocysteine S-Methyltransferase; D002331:Carnitine; D012521:Sarcosine