Taleisnik S, Caligaris L, Beltramino C, Cáceres A
J Endocrinol. 1978 Apr;77(1):11-23. doi: 10.1677/joe.0.0770011.
The effect of frontal hypothalamic deafferentation on the release of LH and FSH was studied in ovariectomized rats. Frontal cuts were placed just in front of the arcuate nucleus, at the posterior border of the optic chiasma (RCS), at the level of the anterior commissure (POS) and in front of the optic chiasma (PCS). Animals with RCS and POS cuts showed vaginal smears with persistent cornification; the other groups had irregular cycles. The concentrations of LH and FSH in the serum increased after ovariectomy in deafferentated animals, but after 4 weeks the levels were lower than in the animals without hypothalamic lesions except for the PCS group. The more caudally that the cuts were located, the lower were the concentrations of hormones in the serum. The injection of repeated doses of oestradiol benzoate resulted in a decrease in serum gonadotrophin of both rats without hypothalamic lesions and RCS rats. Although a greater decrease was observed in the lesioned than in the intact rats, it is believed that such an effect does not indicate an increased sensitivity of deafferentated animals to this steroid. The stimulatory effect of progesterone on LH and FSH release was studied in ovariectomized rats primed with oestradiol benzoate. The responses were unchanged in PCS animals but failed to occur in POS and RCS rats. Measurement of the level of gonadotrophin-releasing hormone in frontal hypothalamic slices from RCS animals showed a decreased level behind the cut and an increased one in front of it, suggesting that perikarya located in front of the section were sending their axons to the mediobasal hypothalamus. It is believed that the blockade of the stimulatory effect on gonadotrophins by frontal hypothalamic deafferentation is due to the transection of these axons. Cuts placed immediately in front of the arcuate nucleus, however, permitted progesterone-induced gonadotrophin release because of incoming neurones containing gonadotrophin-releasing hormone, which end in structures immediately rostral to the cut. The results indicate that effects of both inhibitory and stimulatory ovarian steroid feedback are impaired by frontal hypothalamic deafferentation.
在去卵巢大鼠中研究了下丘脑前部传入神经切断对促黄体生成素（LH）和促卵泡生成素（FSH）释放的影响。在前连合水平（POS）、视交叉后缘（RCS）、视交叉前方（PCS）以及弓状核前方进行额叶切断。接受RCS和POS切断的动物阴道涂片显示持续角化；其他组的月经周期不规律。去传入神经的动物在去卵巢后血清中LH和FSH浓度升高，但4周后，除PCS组外，其水平低于无下丘脑损伤的动物。切断位置越靠尾侧，血清中激素浓度越低。重复注射苯甲酸雌二醇导致无下丘脑损伤的大鼠和RCS大鼠血清促性腺激素减少。虽然损伤大鼠的促性腺激素减少幅度大于完整大鼠，但认为这种效应并不表明去传入神经的动物对这种类固醇的敏感性增加。在预先用苯甲酸雌二醇处理的去卵巢大鼠中研究了孕酮对LH和FSH释放的刺激作用。PCS动物的反应未改变，但POS和RCS大鼠未出现反应。对RCS动物下丘脑前部切片中促性腺激素释放激素水平的测量显示，切断部位后方水平降低，前方水平升高，这表明位于切片前方的神经核向内侧基底下丘脑发送轴突。据信，下丘脑前部传入神经切断对促性腺激素的刺激作用的阻断是由于这些轴突的横断。然而，在弓状核前方立即进行的切断允许孕酮诱导促性腺激素释放，因为含有促性腺激素释放激素的传入神经元终止于切断部位前方紧邻的结构。结果表明，下丘脑前部传入神经切断会损害卵巢类固醇反馈的抑制和刺激作用。
