The effect of estrogen replacement therapy on total plasma homocysteine in healthy postmenopausal women.
OBJECTIVE
To clarify the effect of estrogen on total plasma homocysteine concentration and on the concentration of vitamins required for homocysteine metabolism (folate, vitamin B12, and vitamin B6).


RESULTS
We measured total fasting plasma homocysteine in 16 healthy postmenopausal women before and 6 hours after a methionine load (100 mg/kg); fasting concentrations of folate, vitamin B12, vitamin B6, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were also determined. After 6 months of estrogen replacement therapy with estradiol, 2 mg daily, and 1 cycle of quarterly methoxyprogesterone acetate, 5 mg daily administered on the 91st through 100th days, measurements were repeated. There was no significant change in mean +/- SD fasting homocysteine concentration (8.8+/-2.5 vs 8.5+/-2.0 micromol/L; P=.30); homocysteine concentrations after methionine load increased from 38.8+/-12.3 to 51.1+/-12.5 micromol/L (P=.01). During this time period, no significant changes occurred in the concentrations of folate (11.7+/-4.4 vs 9.8+/-4.1 nmol/L; P=.06), vitamin B12 (394+/-182 vs 411+/-155 pmol/L; P=.40), or vitamin B6 (pyridoxal phosphate) (26+/-21 vs 36+/-25 nmol/L; P=.15). The mean +/- SD concentration of low-density cholesterol declined 20% (from 147+/-32 to 118+/-37 mg/dL) and high-density lipoprotein increased 16% (from 40+/-13 to 46+/-19 mg/dL) during the study period.


CONCLUSIONS
Six months of estrogen replacement therapy did not lower fasting plasma total homocysteine concentrations and raised homocysteine concentrations following a methionine load. Lipid profiles improved significantly during the study period. A reduction in homocysteine concentrations is not likely to contribute to the reduction in cardiovascular events seen with estrogen replacement therapy.
Berger
P B
PB
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic Rochester, Minn 55905, USA.
Herrmann
R R
RR
Dumesic
D A
DA
D000328:Adult; D015914:Estrogen Replacement Therapy; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008715:Methionine / Q000008:administration & dosage / Q000097:blood; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D011736:Pyridoxine / Q000097:blood; D012016:Reference Values; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood
D008055:Lipids; D006710:Homocysteine; D005492:Folic Acid; D008715:Methionine; D011736:Pyridoxine; D014805:Vitamin B 12