Related Experiment Videos
The effect of maternal prolactin infusion during pregnancy on fetal adipose tissue development
1Academic Division of Child Health, School of Human Development, Queen's Medical Centre, University Hospital, Nottingham NG7 2UH, UK.
Insights
Maternal administration of prolactin (PRL) to pregnant rats significantly increased uncoupling protein-1 (UCP1) in fetal and neonatal brown adipose tissue. This suggests prolactin plays a key role in the maturation of brown adipose tissue in developing rat pups.
Area of Science:
- Endocrinology
- Developmental Biology
- Metabolism
Background:
- Brown adipose tissue (BAT) is crucial for thermogenesis, particularly in altricial neonates.
- The role of maternal hormones in fetal and neonatal BAT development is not fully understood.
- Prolactin (PRL) is a key hormone in maternal-fetal physiology, but its specific impact on BAT maturation requires investigation.
Purpose of the Study:
- To investigate the effect of maternal prolactin (PRL) administration on the abundance of uncoupling protein-1 (UCP1) in fetal and neonatal rat brown adipose tissue.
- To determine if maternal PRL influences other markers of brown adipose tissue development, such as lipid droplet content and voltage-dependent anion channel abundance.
- To examine the impact of maternal PRL on fetal and maternal plasma leptin levels.
Main Methods:
- Pregnant rats were infused with recombinant prolactin (PRL) or saline throughout gestation.
- Brown adipose tissue was collected from fetuses and neonates at specific gestational and postnatal ages.
- Uncoupling protein-1 (UCP1) abundance was quantified using immunoblotting and immunocytochemistry.
- Voltage-dependent anion channel abundance and lipid droplet content were also assessed.
- Plasma leptin concentrations were measured in fetuses and mothers.
Main Results:
- Maternal PRL infusion significantly increased UCP1 abundance in fetal (19.5 days gestation) and neonatal (18 hours postnatal) brown adipose tissue.
- Neonatal brown adipose tissue from PRL-exposed pups showed fewer lipid droplets but higher UCP1 levels.
- The abundance of the voltage-dependent anion channel was not affected by maternal PRL.
- Fetal plasma leptin concentrations were elevated in pups born to PRL-infused dams, but maternal leptin levels were unchanged.
Conclusions:
- Maternal prolactin administration promotes the maturation of brown adipose tissue in fetal and neonatal rats.
- These findings suggest a critical role for prolactin in preparing the neonate for thermogenesis shortly after birth.
- The observed changes implicate prolactin in the developmental programming of brown adipose tissue thermogenic capacity.
Abstract:
The present study determines whether maternal administration of prolactin (PRL) to dams promotes the abundance of the brown adipose tissue-specific uncoupling protein-1 (UCP1) in fetal and neonatal rat pups. Recombinant PRL (24 micro g/kg per day), or an equivalent volume of saline, were infused into dams (n=19 per group) throughout pregnancy from 12 h after mating. Interscapular brown adipose tissue was sampled either from fetuses at 19.5 days of gestation (term=21.5 days) or from neonatal rat pups at approximately 18 h after birth. The abundance of UCP1 was determined by immunoblotting on adipose tissue samples from individual pups and pooled from groups of pups. This analysis was complemented by immunocytochemistry on representative adipose tissue samples. Maternal PRL infusion resulted in a greater abundance of UCP1 in fetal rats at 19.5 days of gestation (control: 97.2+/-8.4% reference; PRL: 525.6+/-74.4% reference; P<0.001) and in neonates 18 h after birth. In contrast, the abundance of the outer mitochondrial membrane protein voltage-dependent anion channel was unaffected by PRL. Neonatal adipose tissue sampled from pups born to PRL-infused dams possessed fewer lipid droplets, but more UCP1, as determined by immunocytochemistry. Fetal, but not maternal, plasma leptin concentrations were also increased by maternal PRL administration. In conclusion, as rats are altricial, and the potential thermogenic activity of brown adipose tissue develops over the first few days of postnatal life, these changes prior to, and at the time of, birth implicate PRL in fetal and neonatal adipose tissue maturation.