摘要
本文报道下丘脑-垂体-睾丸间质细胞体外灌流系统及用以研究GnRH激动剂对大鼠性腺轴的作用机理。外源性GnRH或羊LH(oLH)或内源性GnRH(由下丘脑释放的并以其刺激垂体分泌的Bio-LH测定量表示之)刺激2～3次,每次刺激10分钟,间隔2小时,自动收集灌流液(5ml/管),测定其T、P、17α-OHP和Bio-LH。给大鼠隔日注射1μgGnRH-A(D-色~6-GnRH)共5次导致间质细胞T产量下降到对照值的1.5和1.8%,注射15次后17α-OHP下降到对照值的10～41%,而P产量却增加到对照值的234和734%,显示垂体仍能分泌足够的Bio-LH。结果说明GnRH-A有直接抑制17羟化酶活性而导致T及17α-羟孕酮合成下降是GnRH-A抑制性腺功能的原发作用,而垂体失敏和性腺中促性腺激素受体降调节并非主要机制。
A simple in vitro perfusion system of hypothalamo-pituitary-testicular interstitialcells was described to study the mechanism of GnRH agonist on the different levels ofgonadal axis in the rat. The preparation of H-P-gonadal axis was perfused at a rateof 0.5 ml/min with the medium 199. Pulsatile stimulation with exogenous (GnRH orovine LH) or endogenous GnRH and LH released from hypothalamus and pituitary expre-ssed as Bio-LH measured were given 2-3 times, 10 min for each pulse at 2 h interval.Fractions of perfusate were collected every 10 min and assayed for T, P, 17 α-OHP andBio-LH. Five injections of D-Trp^6-GnRH given every other day at a dose of 1 μg sup-pressed T production to an extent about 1.5%to 1.8% of the control levels. After 15injections l7 α-OHP production was reduced to an extent of 10-41% of normal levelswhereas the peak values of P production reached 234% and 734% of the controls in res-ponse to 2 pulses of oLH stimulation respectively, although the Bio-LH peak values werestill about 40-60% of the controls. In conclusion: 1. The direct inhibition of 17α-hydroxylase with subsequent reductionof T and 17α-OHP production and increase of P production appeared to be a primary ac-tion of LHRH-A on testis. 2. That the perfused hypothalamus pituitaries from GnRH-A treated rats were capable of releasing enough quantity of Bio-LH and significantly in-creasing P production seemed to imply that desensitization of pituitary and LH receptordown regulation is unlikely to play an important role in the mechanism by which GnRH-A suppressed steroidogenesis in Leydig cells.
出处
《生殖与避孕》
CAS
CSCD
北大核心
1990年第1期50-55,共6页
Reproduction and Contraception
关键词
GNRH-A
体外灌流
性腺轴
鼠
Hypothalamo-Pituitary Testicular Interstitial cells
In vitro perfusion
GnRH-A
