Lookingland K J, Wise P M, Barraclough C A
Biol Reprod. 1982 Sep;27(2):268-81. doi: 10.1095/biolreprod27.2.268.
We have examined norepinephrine (NE) and dopamine (DA) initial concentrations, rate constants and turnover rates in microdissected regions of the hypothalamus and gonadotropin release in ovariectomized (OVX)estrogen-treated adult control and androgen-sterilized rats (ASR) (50 micrograms testosterone propionate at 5 days of age). When Silastic capsules containing estradiol (E2) were implanted one week after ovariectomy (Day 0) in control rats, afternoon luteinizing hormone (LH) surges occurred on Days 3 and 4. When 2 progesterone (P) silastic capsules were placed s.c. on Day 3 at 0900 h into E2-primed ovariectomized controls, the afternoon LH plasma surge concentrations were markedly amplified. In contrast, identical E2 or E2P treatment of adult ovariectomized ASR had no effect on plasma LH on either Days 3 or 4 after E2 capsule placement. Serum concentration differences of follicle-stimulating hormone (FSH), prolactin (Prl), E2 and P between control rats and ASR and the effects of E2 treatment on these hormone levels also were recorded. In E2-treated ASR, initial steady state concentrations of NE were significantly less than in controls in all brain regions examined. NE turnover rates increased significantly in E2-treated controls at 1500-1700 h compared to those at 1000-1200 h in median eminence (ME), medial preoptic nucleus (MPN), suprachiasmatic nucleus (SCN) but not in arcuate nucleus (AN). No increase in NE turnover rates occurred in MPN and ME and only slight increases in turnovers were observed in SCN and AN in E2-treated ASR during the afternoon. DA turnover rates declined between morning and afternoon in ME of control and ASR. In control rats, DA turnover rates increased during the afternoon in AN and MPN but remained unchanged in these same hypothalamic regions in ASR. A considerable amount of previous evidence suggests that NE may be the neural trigger which evokes the release of luteinizing hormone releasing hormone (LHRH) from ME axon terminals in normal proestrous or in E2-treated ovariectomized rats. The failure of NE to be released into the MPN and ME of ASR may account for the failure of estradiol to induce LH surges in these animals.
我们检测了去卵巢（OVX）并用雌激素处理的成年对照大鼠和雄激素绝育大鼠（ASR）（5日龄时注射50微克丙酸睾酮）下丘脑微切割区域中去甲肾上腺素（NE）和多巴胺（DA）的初始浓度、速率常数和周转率，以及促性腺激素释放情况。在对照大鼠去卵巢（第0天）一周后植入含雌二醇（E2）的硅胶胶囊时，在第3天和第4天出现了下午促黄体生成素（LH）高峰。当在第3天09:00将2个孕酮（P）硅胶胶囊皮下植入经E2预处理的去卵巢对照大鼠时，下午LH血浆高峰浓度明显升高。相比之下，对成年去卵巢ASR进行相同的E2或E2P处理，在植入E2胶囊后的第3天或第4天对血浆LH均无影响。还记录了对照大鼠和ASR之间促卵泡激素（FSH）、催乳素（Prl）、E2和P的血清浓度差异，以及E2处理对这些激素水平的影响。在经E2处理的ASR中，在所检测的所有脑区中，NE的初始稳态浓度均显著低于对照大鼠。与在正中隆起（ME）、内侧视前核（MPN）、视交叉上核（SCN）中1000 - 1200 h时相比，经E2处理的对照大鼠在1500 - 1700 h时NE周转率显著增加，但在弓状核（AN）中未增加。在经E2处理的ASR中，下午MPN和ME中NE周转率未增加，SCN和AN中仅观察到周转率略有增加。对照大鼠和ASR的ME中，DA周转率在上午和下午之间下降。在对照大鼠中，下午AN和MPN中的DA周转率增加，但在ASR的相同下丘脑区域中保持不变。大量先前的证据表明，在正常动情前期或经E2处理的去卵巢大鼠中，NE可能是促使ME轴突终末释放促黄体生成素释放激素（LHRH）的神经触发因素。NE未能释放到ASR的MPN和ME中，可能是雌二醇未能在这些动物中诱导LH高峰的原因。
