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Sex-based differences in serum leptin concentrations from umbilical cord blood at delivery
1Department of Medicine, School of Medicine, Santiago de Compostela University, Spain.
Insights
Newborn girls have significantly higher leptin levels than newborn boys, indicating early sex-based differences in leptin regulation by fetal adipose tissue. These differences emerge before birth, not due to infant size.
Area of Science:
- Endocrinology
- Neonatal Physiology
- Human Development
Background:
- Sex-based differences in serum leptin are known in adolescence and adulthood.
- The developmental origin of these sex-based differences in leptin is not well understood.
- Leptin, a hormone produced by adipose tissue, plays a role in energy balance and metabolism.
Purpose of the Study:
- To investigate the onset of sex-based differences in leptin concentrations.
- To determine if these differences are present at birth in umbilical cord blood.
- To explore potential factors influencing these early sex-based differences.
Main Methods:
- Serum leptin concentrations were measured in umbilical cord blood from 46 healthy infants.
- Maternal blood at delivery was also analyzed for leptin levels.
- Infant and maternal anthropometric data, including weight and placental weight, were collected and analyzed by sex.
Main Results:
- Umbilical cord leptin concentrations were disproportionately high compared to maternal levels.
- Infant leptin levels showed wide variation and did not correlate with growth parameters.
- Significantly higher leptin concentrations were found in female infants (12.9 µg/L) compared to male infants (6.8 µg/L).
- No significant difference in maternal leptin levels was observed based on the sex of the infant.
- Heavier placental weight was noted in female infants, but other growth parameters did not differ by sex.
Conclusions:
- Sex-based differences in leptin concentrations are established by birth.
- These differences may originate from sex-specific regulation of leptin production by fetal adipose tissue.
- Placental weight differences may contribute to the observed sex-based variations in cord blood leptin.
Abstract:
Sex-based differences in serum leptin concentrations have been reported in adolescence and adulthood. To discover when such differences were generated, serum leptin concentrations were measured in umbilical cord blood from 46 healthy infants and in the mother's blood at delivery. Considering the respective body weights of the mothers and infants (68.5 +/- 1.3 kg and 3.3 +/- 0.0 kg), umbilical cord concentrations of leptin were disproportionately high in the infants (9.4 +/- 1.2 micrograms/l) compared with those in the mothers (18.7 +/- 1.3 micrograms/l). There was a wide variation in the infants leptin values (1.2 +/- 56.8 micrograms/l) that did not correlate with height, weight, cephalic circumference, or any other growth-related parameter. The most striking differences emerged when results were analysed by sex: umbilical cord concentrations of leptin in the girls (12.9 +/- 2.2 micrograms/l) were significantly (P < 0.01) greater than those in the boys (6.8 +/- 0.9 micrograms/l), although no differences in leptin concentrations were observed between the mothers who gave birth to a girl (19.5 +/- 2.2 micrograms/l) and those who gave birth to a boy (18.1 +/- 1.7 micrograms/l). The sex-based differences were not attributable to any growth-related differences between the sexes, except heavier placental weights in the girls (P < 0.007) than in the boys. These differences in leptin concentrations may reflect a sex-based difference in the regulation of leptin production by the fetal adipose tissue.