Free-to-total leptin ratio in maternal plasma is constant throughout human pregnancy.
To clarify the mechanism of leptin resistance during pregnancy, we measured plasma leptin concentrations, free to total leptin ratio (percent free leptin) and soluble leptin receptor concentrations in pregnant women, and compared the results with those in non-pregnant women. We collected plasma samples from 23 non-pregnant and 31 pregnant women in the third trimester. Plasma samples from 5 pregnant women were collected longitudinally in each trimester. Plasma leptin concentrations in pregnant women in the second trimester (17.4 +/- 3.2 ng/ml) were higher than those in the first trimester of pregnancy (11.0 +/- 2.8 ng/ml, n = 5), as previously reported. However, percent free leptin did not change significantly throughout pregnancy. Percent free leptin correlated with total leptin concentrations (ng/ml) in non-pregnant women (r = 0.727, P < 0.0001), but not in women in the third trimester of pregnancy (r = 0.006). Constant percent free leptin during pregnancy despite increased leptin concentrations indicates increased leptin binding capacity in pregnant women, that might partly contribute to the establishment of leptin resistance. On the other hand, soluble leptin receptor concentrations showed significant negative correlation with BMI and plasma leptin concentrations in pregnant women (r = -0.470, P < 0.01 and r = -0.493, P < 0.01, respectively) but not in non-pregnant women. These data suggest the possibility that soluble leptin receptor is a minor component of leptin binding capacity in the plasma of pregnant women.
Department of Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
Mercy A
MA
Nuamah
Norimasa
N
Sagawa
Shigeo
S
Yura
Hiroko
H
Mise
Hiroaki
H
Itoh
Yoshihiro
Y
Ogawa
Kazuwa
K
Nakao
Shingo
S
Fujii
D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008137:Longitudinal Studies; D008875:Middle Aged; D009994:Osmolar Concentration; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011956:Receptors, Cell Surface / Q000097:blood*; D054411:Receptors, Leptin
C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin