Zeinoaldini S, Swarts J J M, Van de Heijning B J M
Human and Animal Physiology Group, Animal Sciences Group, Wageningen University, Wageningen, The Netherlands.
Horm Res. 2006;66(4):169-74. doi: 10.1159/000094144. Epub 2006 Jun 23.
BACKGROUND/AIMS: Central but also peripheral IGF-1 is suggested to play a role in the initiation of puberty as it directly affects GnRH synthesis and release. A possible intermediate in the effects of IGF-1 on puberty might be the adiposity-signaling hormone leptin, whose plasma levels are decreased in food-restricted (FR) rats.
IGF-1 was chronically centrally infused in 23-day-old prepubertal female rats which were either normally fed or 30% FR, and the effects on time of vaginal opening (VO) and plasma leptin levels were monitored.
FR treatment postponed time of VO and decreased plasma leptin levels. In normally fed rats centrally infused with IGF-1, time of VO was found to be postponed to the same extent as FR treatment did. The IGF-1 infusion did not affect plasma leptin levels in normally fed animals but increased leptin levels in the FR group compared to controls. Daily food intake was equal between all groups but body weight course was lower in FR rats. IGF-1 treatment did not significantly affect food intake or body weight course.
FR treatment delays the moment of vaginal opening to the same extent as observed in normally fed rats that were centrally infused with IGF-1.
背景/目的：中枢和外周胰岛素样生长因子-1（IGF-1）均被认为在青春期启动过程中发挥作用，因为它直接影响促性腺激素释放激素（GnRH）的合成与释放。IGF-1对青春期影响的一个可能中间环节或许是脂肪信号激素瘦素，在食物受限（FR）大鼠中其血浆水平会降低。
对23日龄青春期前的雌性大鼠进行慢性中枢注射IGF-1，这些大鼠分为正常喂养组或30%食物受限组，并监测其对阴道开口时间（VO）和血浆瘦素水平的影响。
食物受限处理使阴道开口时间推迟，并降低了血浆瘦素水平。在正常喂养且中枢注射IGF-1的大鼠中，发现阴道开口时间推迟的程度与食物受限处理相同。IGF-1注射对正常喂养动物的血浆瘦素水平无影响，但与对照组相比，食物受限组的瘦素水平升高。所有组的每日食物摄入量相等，但食物受限大鼠的体重增长较低。IGF-1处理对食物摄入量或体重增长无显著影响。
食物受限处理使阴道开口时间推迟的程度与正常喂养且中枢注射IGF-1的大鼠相同。
