TAMOXIFEN AND ESTROGEN LOWER CIRCULATING LIPOPROTEIN(A) CONCENTRATIONS IN HEALTHY POSTMENOPAUSAL WOMEN

TAMOXIFEN AND ESTROGEN LOWER CIRCULATING LIPOPROTEIN(A) CONCENTRATIONS IN HEALTHY POSTMENOPAUSAL WOMEN

Shewmon D A; Stock J L; Rosen C J; Heiniluoma K M; Hogue M M; Morrison A; Doyle E M; Ukena T; Weale V; Baker S

Arteriosclerosis and Thrombosis

1994

1994-10

Data in the literature suggest that circulating levels of lipoprotein(a) [Lp(a)] and insulinlike growth factor I (IGF-I) respond similarly to therapy with growth hormone, estrogen, or tamoxifen. To more clearly document these relations, we designed a randomized, double-blind, placebo-controlled study of the effects of tamoxifen and continuous estrogen on circulating levels of Lp(a), IGF-I, and IGF binding protein 3 (IGFBP-3) in healthy postmenopausal women. Both estrogen and tamoxifen decreased serum levels of IGF-I to 30% below baseline during the 3 months of treatment, while IGFBP-3 levels were unchanged. Plasma Lp(a) levels decreased to 24% below baseline after 1 month of treatment with either estrogen or tamoxifen (P < .05 for estrogen only); after 3 months Lp(a) decreased to 34% below baseline with tamoxifen therapy (P < .05) but returned to only 16% below baseline with estrogen. The correlation between Lp(a) and IGF-I was highly significant (P < .0001). We conclude that (1) tamoxifen lowers plasma Lp(a) levels in healthy postmenopausal women, (2) the suppressive effects of tamoxifen and estrogen on circulating Lp(a) concentration diverge after the first month of therapy, and (3) circulating levels of Lp(a) and IGF-I are strongly correlated with each other, an indication that they may share regulatory influences.

binding-proteins; breast-cancer; cardiovascular risk-factors; Cardiovascular System & Cardiology; coronary heart-disease; estrogen replacement; growth factor-i; insulin-like growth factor i; lipoprotein(a); lp(a) lipoprotein; menopause; replacement therapy; serum lipoprotein(a); smooth-muscle cells; somatomedin-c; tamoxifen; therapy

Journal Article

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1586-1593

10

14