Laboratory of Histology and Embryology, School of Medicine, University of Athens, Athens, Greece.
Neuroendocrinology. 2010;92(4):235-45. doi: 10.1159/000321393. Epub 2010 Oct 22.
BACKGROUND/AIMS: Studies conducted in adult rats have shown that increased fat intake affects brain energy homeostasis and stress response. The neuroendocrine circuits controlling the aforementioned functions continue to mature during puberty. The aim of the present study was to investigate whether post-weaning high-fat consumption can modify the endocrine responses of pubertal rats to an acute stress.
Weaning male and female Wistar rats on postnatal day (P) 22 were fed either a high-fat (HF; 45% calories from fat) or a control (10% calories from fat) diet and were sacrificed on the individual day of puberty onset (between P35 and P42) under basal conditions or 4 h after swimming stress. Plasma insulin, leptin and corticosterone levels were determined by radioimmunoassay and the respective receptors in the hypothalamus and hippocampus were determined by Western blot analysis.
Stressed HF-fed males showed a smaller increase in plasma insulin levels than chow-fed males. Their leptin receptor levels were reduced in the hypothalamus, but not in the hippocampus, and their glucocorticoid receptor levels were increased in the hypothalamus compared to stressed chow-fed males. HF-fed females were nonresponsive to stress-induced alterations in plasma glucose and corticosterone levels, as well as to hippocampal insulin receptors following stress. Several sex differences were also revealed in the endocrine responses of HF-fed animals following stress.
These data show that consumption of high-fat foods during preadolescence can modify the endocrine responses to an acute stress by affecting both stress and metabolic mediators in a sexually dimorphic manner.
背景/目的：在成年大鼠中进行的研究表明，脂肪摄入量的增加会影响大脑的能量稳态和应激反应。控制上述功能的神经内分泌回路在青春期仍在继续成熟。本研究的目的是研究青春期后高脂肪饮食是否可以改变幼鼠对急性应激的内分泌反应。
我们在出生后第 22 天（P）对雄性和雌性 Wistar 大鼠进行断奶，并分别喂食高脂肪（HF；45%的卡路里来自脂肪）或对照（10%的卡路里来自脂肪）饮食，并在青春期开始的当天（P35 至 P42 之间）在基础条件下或游泳应激后 4 小时处死。通过放射免疫测定法测定血浆胰岛素、瘦素和皮质酮水平，并通过 Western blot 分析测定下丘脑和海马中的相应受体。
应激的 HF 喂养雄性大鼠的血浆胰岛素水平升高幅度小于对照喂养雄性大鼠。它们的瘦素受体在下丘脑中减少，但在海马体中没有减少，而它们的糖皮质激素受体在下丘脑中比应激对照喂养雄性大鼠增加。HF 喂养的雌性大鼠对应激引起的血糖和皮质酮水平变化以及应激后海马胰岛素受体无反应。应激后 HF 喂养动物的内分泌反应也显示出一些性别差异。
这些数据表明，青春期前摄入高脂肪食物可以通过以性别二态的方式影响应激和代谢介质来改变对急性应激的内分泌反应。
