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Leptin, insulin, insulin‐like growth factors and their binding proteins in cord serum: insight into fetal growth and discordancy
Author(s) -
Davidson S.,
Hod M.,
Merlob P.,
Shtaif B.
Publication year - 2006
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2006.02632.x
Subject(s) - medicine , endocrinology , leptin , insulin , insulin like growth factor , birth weight , monozygotic twin , anthropometry , gestational age , hormone , growth factor , biology , pregnancy , obesity , receptor , genetics
Summary Objective Singleton infants with intrauterine growth restriction have an adaptive hormonal profile characterized by decreased levels of IGF‐1, IGF‐2, IGFBP‐3 and insulin and elevated levels of IGFBP‐1 and IGFBP‐2. This study examined the association between cord serum levels of six growth factors and anthropometric features at birth in twins in order to determine the intrauterine growth factor interactions and to characterize the specific hormonal profile of small discordant twins. Design Prevalent case‐control study. Patients Twenty pairs of discordant twins (5 monozygotic, 15 dizygotic) and 20 pairs of concordant twins (6 monozygotic, 14 dizygotic) matched for gestational age. Measurements Cord blood levels of IGF‐1, IGF‐2, IGFBP‐1, IGFBP‐3, insulin, leptin and anthropometric measurements at birth. Intra‐ and inter‐pair differences and correlation coefficients were calculated, and the data were fitted to multivariate regression models. Results In both discordant and concordant groups, the smaller twins had a significantly lower level of IGF‐1 ( P < 0·03) and significantly higher level of IGFBP‐1 ( P < 0·02) than their larger cotwins. IGFBP‐1 was inversely correlated with IGF‐1 ( P < 0·05). Insulin levels were significantly higher in the smaller discordant than the smaller concordant twins ( P < 0·001) and in the larger discordant than the larger concordant twins ( P < 0·004). Among the monozygotic twins, the leptin level was significantly higher in the larger discordant than the larger concordant twins ( P < 0·025). Percentage birth weight discordancy was statistically correlated with twin‐pair differences in IGF‐1 and IGFBP‐1. Conclusions Of the six factors studied, IGF‐1 appears to be the main indicator of intrauterine growth. Twin discordancy may involve compensatory rather than adaptive mechanisms or a multihormone relative resistance syndrome.