Bispham Jayson, Budge Helen, Mostyn Alison, Dandrea Jennifer, Clarke Lynne, Keisler Duane H, Symonds Michael E, Stephenson Terence
Academic Division of Child Health, School of Human Development, University Hospital, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
Pediatr Res. 2002 Jul;52(1):85-90. doi: 10.1203/00006450-200207000-00016.
The influence of route of delivery, ambient temperature, maternal dexamethasone treatment, and postnatal age on plasma concentrations of leptin or leptin mRNA abundance in perirenal adipose tissue was examined from 6-h-old lambs, born vaginally or delivered by cesarean section into warm (30 degrees C) or cool (15 degrees C) ambient temperatures, and from cesarean section-delivered lambs whose mothers had been treated with dexamethasone beginning 2 d before parturition. The ontogeny of leptin during the first month of postnatal life was also examined. In lambs born into a cool ambient temperature, but not in those born to dexamethasone-treated mothers, leptin mRNA abundance decreased within 6 h of birth. Plasma concentrations of leptin decreased during the first 6 h of life, an adaptation delayed by cesarean section birth. After the first day of postnatal life, both plasma concentrations of leptin and its mRNA increased to peak at 7 d of age and were positively correlated with each other, as well as with whole-body and perirenal adipose tissue weights. A similar relationship was not observed after 7 d of age, as plasma leptin declined despite an increase in adipose tissue weight. In conclusion, route of delivery, ambient temperature, or maternal dexamethasone therefore delays the rate of leptin disappearance after birth. Concomitantly, leptin abundance was only associated with body and adipose tissue weights for 1 week after birth, which may be coincident with the onset of peak lactation and the time at which nutrient supply should no longer be limiting to the neonate.
研究了分娩途径、环境温度、母体地塞米松治疗及出生后年龄对6小时龄羔羊血浆瘦素浓度或肾周脂肪组织中瘦素mRNA丰度的影响。这些羔羊通过阴道分娩或剖宫产出生，出生后置于温暖（30℃）或凉爽（15℃）的环境温度中，还有一些剖宫产出生的羔羊，其母亲在分娩前2天开始接受地塞米松治疗。同时也研究了出生后第一个月内瘦素的个体发育情况。出生于凉爽环境温度下的羔羊，而非母亲接受地塞米松治疗的羔羊，出生后6小时内瘦素mRNA丰度下降。出生后最初6小时内血浆瘦素浓度下降，剖宫产出生会延迟这种适应性变化。出生后第一天后，血浆瘦素浓度及其mRNA均在7日龄时升至峰值，且二者呈正相关，同时也与全身及肾周脂肪组织重量呈正相关。7日龄后未观察到类似关系，因为尽管脂肪组织重量增加，但血浆瘦素却下降了。总之，分娩途径、环境温度或母体地塞米松会延迟出生后瘦素消失的速度。同时，出生后1周内瘦素丰度仅与体重和脂肪组织重量相关，这可能与泌乳高峰期的开始以及营养供应不再限制新生儿的时间相吻合。
