Insulin-like growth factor binding protein-1 (IGFBP-1) and IGF-I during oral and transdermal estrogen replacement therapy: relation to lipoprotein(a) levels.
Low levels of insulin-like growth factor binding protein-1 (IGFBP-1) have recently been associated with several risk factors for cardiovascular disease. The effects of estrogen replacement therapy (ERT) on plasma IGFBP-1 levels are, however, unclear. A double-blind, placebo-controlled study for 6 months was conducted in 73 hysterectomized postmenopausal women randomized into two groups: oral estradiol (E2) valerate, 2 mg/day (n = 35) and transdermal E2 gel, 1 mg/day (n=38). Plasma IGFBP-1, insulin-like growth factor-I (IGF-I) and lipoprotein(a) (Lp(a)) were determined at baseline, 3 and 6 months. The groups were similar for age and BMI. The baseline levels of estrone (E1), E2, IGFBP-1, IGF-I and Lp(a) did not differ between the groups. During treatment, serum estradiol concentrations increased in both groups. During oral ERT, IGFBP-1 levels increased by 104% (P<0.001), whereas IGF-I levels decreased by 13% (mean, P<0.05). IGF-I and IGFBP-1 levels remained unchanged in the transdermal group. Lp(a) levels decreased by 23% (median, P<0.001) in the oral group, but were unaffected by transdermal therapy. The change in IGFBP-1 concentrations during oral ERT showed an inverse correlation to that in Lp(a) (r = -0.40, P<0.05, Spearman correlation). In conclusion, oral ERT seems to enhance plasma levels of IGFBP-1, which may be one reason for the reduced Lp(a) levels.
Paassilta
M
M
Department of Internal Medicine and Biocenter Oulu, University of Oulu, Kajaanintie 50, FIN-90220, Oulu, Finland.
Karjalainen
A
A
Kervinen
K
K
Savolainen
M J
MJ
Heikkinen
J
J
Bäckström
A C
AC
Kesäniemi
Y A
YA
D000279:Administration, Cutaneous; D000284:Administration, Oral; D000368:Aged; D002318:Cardiovascular Diseases / Q000209:etiology / Q000517:prevention & control; D004311:Double-Blind Method; D004958:Estradiol / Q000008:administration & dosage*; D015914:Estrogen Replacement Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007044:Hysterectomy; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000032:analysis / Q000187:drug effects*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000187:drug effects*; D017270:Lipoprotein(a) / Q000032:analysis / Q000187:drug effects*; D008875:Middle Aged; D017698:Postmenopause; D011336:Probability; D012680:Sensitivity and Specificity; D012984:Software
D018970:Insulin-Like Growth Factor Binding Protein 1; D017270:Lipoprotein(a); D004958:Estradiol; D007334:Insulin-Like Growth Factor I