Ramaley J A, Sieck G
Neuroendocrinology. 1975;18(1):55-64. doi: 10.1159/000122383.
All neural connections entering the hypothalamus from the anterior direction were severed by means of a Halász knife-cut in female rats at 22 days of age. The rats were then examined for vaginal opening and ovulation. At intervals blood samples were collected by cardiac puncture for the measurement of serum corticosterone (B). Unoperated rats showed vaginal opening at 36.5 +/- 2.1 days and ovulation within 2 days. A significant difference was found between B at 08.00 h and 18.00 h at the first sample interval chosen (28 days of age) and thereafter. Animals given sham surgery showed vaginal opening late (44.2 +/- 3.2 days, p smaller than 0.05) but ovulated within 2 days. These animals also had a significant 08.00-18.00 difference in B from day 28 on. Rats with frontal cuts in front of the suprachiasmatic nucleus (SCN) showed precocious vaginal opening (27.2 +/- 2.3 days, p smaller than 0.05) and early ovulation (28.2 +/- 0.7 days). A 08.00-18.00 difference was noted at 28 days of age but was lost after ovariectomy at 47 days of age. Implantation of a silastic estradiol benzoate capsule restored the 08.00-18.00 difference (p smaller than 0.01). Animals with cuts behind the optic chiasm (posterior frontal cuts) all showed early vaginal opening; some rats then ovulated (at 42.3 +/- 3.8 days) while others did not. No difference could be detected in the position of the cuts although there appeared to be more damage to the region just behind the SCN in the latter group. No 08.00-18.00 difference in B was found in the nonovulatory group and no difference was found in the ovulatory group until 44 days of age. It can be concluded that an isolated hypothalamic island containing the SCN will generate signals sufficient for precocious ovulation although subsequent ovulatory cycles are not regular.
在22日龄的雌性大鼠中，通过哈拉斯（Halász）刀切术切断了所有从前部方向进入下丘脑的神经连接。然后对这些大鼠进行阴道开口和排卵检查。每隔一段时间通过心脏穿刺采集血样以测量血清皮质酮（B）。未手术的大鼠在36.5±2.1天出现阴道开口，并在2天内排卵。在所选的第一个采样间隔（28日龄）及之后，发现08:00和18:00时的B值存在显著差异。接受假手术的动物阴道开口较晚（44.2±3.2天，p小于0.05），但在2天内排卵。从28日龄起，这些动物在08:00 - 18:00时的B值也存在显著差异。在视交叉上核（SCN）前方进行额叶切割的大鼠出现早熟阴道开口（27.2±2.3天，p小于0.05）和早期排卵（28.2±0.7天）。在28日龄时观察到08:00 - 18:00的差异，但在47日龄卵巢切除后这种差异消失。植入含苯甲酸雌二醇的硅橡胶胶囊可恢复08:00 - 18:00的差异（p小于0.01）。在视交叉后方进行切割（额叶后部切割）的动物均出现早期阴道开口；一些大鼠随后排卵（在42.3±3.8天），而另一些则不排卵。虽然在切割位置上未检测到差异，但后一组中SCN后方区域似乎损伤更大。在未排卵组中未发现08:00 - 18:00的B值差异，在排卵组中直到44日龄才发现差异。可以得出结论，一个孤立的包含SCN的下丘脑岛将产生足以导致早熟排卵的信号，尽管随后的排卵周期并不规律。
