Dada M O, Rodriguez-Sierra J F, Clough R W, Garner L L, Blake C A
Endocrinology. 1985 Jan;116(1):246-51. doi: 10.1210/endo-116-1-246.
We studied whether an increase in the basal LH release rate and/or the anterior pituitary gland (APG) LH response to LHRH is involved in maintaining normal or near-normal serum LH levels in monosodium L-glutamate (MSG)-treated rats which have small APGs for their body weight. Female rats were injected with MSG (4 mg/g BW) or saline on days 1, 3, 5, 7, and 9 after birth (day of birth = 0). At 8-9 weeks of age, saline-treated and MSG-treated rats were ovariectomized, and 7 days later, they were decapitated. Trunk blood was collected from 18 controls and 19 MSG-treated rats, and serum LH concentrations were measured by RIA. APGs were bisected and each hemi-APG was placed in culture medium for a 30-min preincubation period, followed by two 30-min incubation periods during which water or 10 or 30 ng LHRH were added to the medium. Despite the fact that the APGs of the MSG-treated rats were half the size of those of the saline-treated rats, the serum LH levels in the 2 groups were not different. Basal LH release rates (the response to water) and LHRH-induced LH release per mg APG were increased in MSG-treated rats. Calculation of the basal LH release rates and LHRH-induced LH release on the basis of the entire weights of the APGs showed no differences between the MSG-treated rats and the controls. In 6 additional control and 6 additional MSG-treated rats, the APG LH concentration was measured and was not different between the 2 groups. The results suggest that increases in both the basal LH release rate per mg APG and the amount of LH released per mg APG in response to LHRH are of importance in the maintenance of normal or near-normal serum LH concentrations in MSG-treated rats with small APGs.
我们研究了基础促黄体生成素（LH）释放率的增加和/或垂体前叶（APG）对促性腺激素释放激素（LHRH）的LH反应是否参与维持体重相对较小的L-谷氨酸单钠（MSG）处理大鼠的正常或接近正常血清LH水平。雌性大鼠在出生后第1、3、5、7和9天（出生日=0）注射MSG（4mg/g体重）或生理盐水。8-9周龄时，对生理盐水处理组和MSG处理组大鼠进行卵巢切除，7天后断头。采集18只对照大鼠和19只MSG处理大鼠的躯干血，用放射免疫分析法（RIA）测定血清LH浓度。将APG切成两半，每个半APG置于培养基中预孵育30分钟，随后进行两个30分钟的孵育期，在此期间向培养基中加入水或10或30ng LHRH。尽管MSG处理大鼠的APG大小仅为生理盐水处理大鼠的一半，但两组的血清LH水平并无差异。MSG处理大鼠每毫克APG的基础LH释放率（对水的反应）和LHRH诱导的LH释放增加。根据APG的总重量计算基础LH释放率和LHRH诱导的LH释放，发现MSG处理大鼠与对照大鼠之间没有差异。在另外6只对照大鼠和6只MSG处理大鼠中，测定了APG LH浓度，两组之间没有差异。结果表明，每毫克APG基础LH释放率的增加以及每毫克APG对LHRH反应时LH释放量的增加，对于维持APG较小的MSG处理大鼠正常或接近正常的血清LH浓度具有重要意义。
