Gibson M J, Kasowski H, Dobrjansky A
Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029.
Biol Reprod. 1994 Mar;50(3):680-5. doi: 10.1095/biolreprod50.3.680.
Adult hypogonadal (hpg) mice, lacking GnRH, have infantile reproductive systems and levels of pituitary gonadotropins that are lower than normal. The mutant mice respond to brain grafts containing GnRH neurons with gonadal development and increased production of gonadotropins. In view of the substantial literature regarding the nature and necessity of pulsatile GnRH stimulation of gonadotropins, we were not surprised in earlier studies to find that the majority of hpg mice with successful grafts have pulsatile LH secretion. It is not known, however, why LH pulsatility was undetectable in some animals with significant gonadal development. The present experiment was intended to determine the degree to which hpg mice respond to continuous infusion of GnRH via osmotic minipumps. Unexpectedly, female hpg mice exhibited dramatic ovarian and uterine growth after 15 or 30 days of continuous exposure to GnRH, with five- and eightfold increases in ovarian and uterine weights, respectively. Despite evidence of increased gonadotropin secretion in the treated hpg mice, pituitary stores of FSH and LH remained low. Similar treatment of normal female mice for 15 days also depleted pituitary concentrations of LH and FSH without significantly altering gonadal weights or plasma gonadotropin levels. It is clear from the present that inferences of pulsatile GnRH secretion based on stimulation of gonadal development in hpg mice should be made with caution.
成年性腺功能减退（hpg）小鼠缺乏促性腺激素释放激素（GnRH），其生殖系统呈幼稚状态，垂体促性腺激素水平低于正常水平。这些突变小鼠对含有GnRH神经元的脑移植有反应，表现为性腺发育以及促性腺激素分泌增加。鉴于有大量关于GnRH脉冲式刺激促性腺激素的性质和必要性的文献，我们在早期研究中发现大多数移植成功的hpg小鼠有LH脉冲式分泌并不感到惊讶。然而，尚不清楚为什么在一些性腺有显著发育的动物中检测不到LH脉冲性。本实验旨在确定hpg小鼠对通过渗透微型泵持续输注GnRH的反应程度。出乎意料的是，雌性hpg小鼠在持续暴露于GnRH 15天或30天后，卵巢和子宫出现显著生长，卵巢和子宫重量分别增加了5倍和8倍。尽管在接受治疗的hpg小鼠中有促性腺激素分泌增加的证据，但垂体中FSH和LH的储备仍然很低。对正常雌性小鼠进行15天的类似治疗也会使垂体中LH和FSH的浓度降低，而不会显著改变性腺重量或血浆促性腺激素水平。从目前的情况来看，基于hpg小鼠性腺发育刺激来推断GnRH脉冲式分泌时应谨慎。
