Hormone interactions regulating energy balance during pregnancy
S R Ladyman1, R A Augustine, D R Grattan
1Department of Anatomy and Structural Biology & Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand.
Journal of Neuroendocrinology
|May 12, 2010
Summary
Pregnancy increases appetite and food intake, leading to leptin resistance. Placental lactogen, mimicking prolactin, appears to mediate this resistance, impacting appetite regulation during gestation.
Area of Science:
- Reproductive biology
- Neuroendocrinology
- Metabolic regulation
Background:
- Pregnancy necessitates increased energy intake for fetal development and lactation.
- Pregnant individuals develop resistance to leptin's appetite-suppressing effects.
- This resistance is crucial for maintaining energy balance despite hormonal changes.
Purpose of the Study:
- To investigate the mechanisms underlying pregnancy-induced leptin resistance.
- To identify hormones mediating leptin resistance during pregnancy.
- To explore the impact of leptin resistance on glucose homeostasis.
Main Methods:
- Studies were conducted in rat models, including pseudopregnant rats.
- Investigated gene expression (neuropeptide Y, pro-opiomelanocortin, leptin receptor) in hypothalamic nuclei.
- Administered ovine prolactin via chronic intracerebroventricular (i.c.v.) infusion.
Main Results:
- Pregnancy in rats is associated with altered hypothalamic gene expression and reduced leptin signaling.
- Leptin resistance during pregnancy may contribute to central insulin resistance and altered glucose homeostasis.
- Prolactin/placental lactogen infusion mimicked pregnancy effects, blocking leptin's anorectic response.
Conclusions:
- Placental lactogen secretion is implicated in mediating hormone-induced leptin resistance during pregnancy.
- This resistance likely involves pathways downstream of primary leptin-responsive neurons.
- Hormonal adaptations during pregnancy significantly alter hypothalamic pathways regulating body weight homeostasis.
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