Different effects of oral conjugated equine estrogens and transdermal estrogen on undercarboxylated osteocalcin concentration in postmenopausal women.
OBJECTIVE
Undercarboxylated osteocalcin (ucOC) is a sensitive marker of vitamin K status, and triglyceride (TG) has been shown to be the main transporter of vitamin K. In the present study, we examined the difference between ucOC concentrations in postmenopausal women receiving hormone therapy (HT) with oral conjugated equine estrogens (CEE) and transdermal estradiol (TE2). We also examined the associations of ucOC concentration with estradiol concentration and TG.


METHODS
Ninety-two postmenopausal women were recruited for this study. Serum concentrations of ucOC, intact osteocalcin, estradiol, and TG were measured before and after 12 months of HT. Forty-six women received oral administration of 0.625 mg of CEE and 2.5 mg of medroxyprogesterone acetate daily, and 46 women received transdermal administration of 50 mug of 17beta-estradiol twice weekly and 2.5 mg of medroxyprogesterone acetate daily.


RESULTS
The ucOC concentration in women during HT with oral CEE was significantly (P < 0.01) lower than that in women during HT with TE2. Serum estradiol concentrations during HT with CEE showed a significant inverse correlation with ucOC concentrations and the ratio of ucOC/OC during HT (P < 0.05 and P < 0.01, respectively). In addition, the serum ucOC concentration in women with an increased percentage of change in TG was significantly (P < 0.01) lower than that in women with a decreased percentage of change in TG during HT with oral CEE.


CONCLUSIONS
The effect of HT with TE2 on ucOC concentration in women is weaker than the effect of HT with oral CEE. Suppression of ucOC concentration in postmenopausal women during HT with oral CEE might be associated with the effect of vitamin K through increased TG induced by oral CEE.
Yasui
Toshiyuki
T
Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan. yasui@clin.med.tokushima-u.ac.jp
Uemura
Hirokazu
H
Tomita
Junko
J
Umino
Yuka
Y
Yamada
Masayo
M
Kuwahara
Akira
A
Matsuzaki
Toshiya
T
Maegawa
Masahiko
M
Miura
Masakazu
M
Irahara
Minoru
M
D000279:Administration, Cutaneous; D000284:Administration, Oral; D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000652:urine; D015519:Bone Density; D004958:Estradiol / Q000008:administration & dosage*; D015914:Estrogen Replacement Therapy; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood / Q000187:drug effects*; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D017698:Postmenopause; D016896:Treatment Outcome; D014280:Triglycerides / Q000097:blood*
D000596:Amino Acids; D004966:Estrogens, Conjugated (USP); D014280:Triglycerides; D015675:Osteocalcin; D004958:Estradiol; C036020:deoxypyridinoline; D000469:Alkaline Phosphatase