Bronson F H, Heideman P D
Department of Zoology, University of Texas, Austin 78712.
Am J Physiol. 1990 Jul;259(1 Pt 2):R25-31. doi: 10.1152/ajpregu.1990.259.1.R25.
These studies focused on the phenomenon of "catch-up" pubertal development. Circulating levels of several hormones were characterized in 8-wk-old female rats whose growth and reproductive development had been blocked before puberty by restricting their food intake. Some of these females were fed ad libitum for 24 h to initiate rapid pubertal development. Blood levels of luteinizing hormone (LH) and growth hormone (GH) were suppressed by food restriction and then partially restored to adult diestrus levels by 24 h of ad libitum feeding. Prolactin titers were also suppressed by food restriction but not significantly elevated by 24 h of ad libitum feeding. Circulating levels of follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) were unaffected by either treatment. It is concluded that GH could play an active supplementary role to LH in eliciting catch-up pubertal development but that FSH and TSH could play only passive roles at best. The role of prolactin remains uncertain. On a finer time scale, when food-restricted females were examined in relation to the time of day at which they were fed, most showed high-amplitude LH pulses 2-4 h after eating but rarely at any other time. Thus under some conditions LH secretion can be modulated by food intake on an almost hour-by-hour basis. Overall, blood levels of corticosterone were generally but not always inversely correlated with the frequency of LH pulsing in these experiments. Finally, the present results argue against the concept that puberty is dependent on a critical whole body characteristic.(ABSTRACT TRUNCATED AT 250 WORDS)
这些研究聚焦于青春期“追赶式”发育现象。对8周龄雌性大鼠的几种激素循环水平进行了表征，这些大鼠在青春期前因食物摄入受限，其生长和生殖发育受到了抑制。其中一些雌性大鼠自由进食24小时以启动快速青春期发育。促黄体生成素（LH）和生长激素（GH）的血液水平因食物限制而受到抑制，然后通过24小时自由进食部分恢复到成年动情间期水平。催乳素滴度也因食物限制而受到抑制，但24小时自由进食后未显著升高。促卵泡生成素（FSH）和促甲状腺激素（TSH）的循环水平不受任何一种处理的影响。得出的结论是，在引发追赶式青春期发育方面，GH可能对LH起到积极的补充作用，但FSH和TSH充其量只能起到被动作用。催乳素的作用仍不确定。在更精细的时间尺度上，当对食物受限的雌性大鼠在进食时间方面进行检查时，大多数在进食后2 - 4小时出现高幅度LH脉冲，而在其他时间很少出现。因此，在某些情况下，LH分泌几乎可以逐小时受到食物摄入的调节。总体而言，在这些实验中，皮质酮的血液水平通常但并非总是与LH脉冲频率呈负相关。最后，目前的结果反对青春期依赖于关键全身特征这一概念。（摘要截断于250字）
