Free-to-total leptin ratio in maternal plasma is constant throughout human pregnancy

Mercy A. Nuamah, Norimasa Sagawa, Shigeo Yura, Hiroko Mise, Hiroaki Itoh, Yoshihiro Ogawa, Kazuwa Nakao, Shingo Fujii

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)421-428
Number of pages8
JournalEndocrine Journal
Issue number4
Publication statusPublished - Aug 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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