Lincoln G A, Fraser H M, Abbott M P
J Reprod Fertil. 1986 Jul;77(2):587-97. doi: 10.1530/jrf.0.0770587.
Adult Soay rams were infused for 21 days with 50 micrograms buserelin/day, using s.c. implanted osmotic mini-pumps. The continuous treatment with this LHRH agonist induced a supraphysiological increase in the blood concentrations of LH (15-fold) and testosterone (5-fold) followed by a decrease below pre-treatment values after 10 days. The blood concentrations of FSH showed only a minimal initial increase but the subsequent decrease was dramatic, occurring within 1 day. By Day 10 of treatment, the blood concentrations of all 3 hormones were low or declining, LH pulses were absent in the serial profiles based on 20-min blood samples and the administration of LHRH antiserum failed to affect the secretion of LH or testosterone. By Day 21, the secretion of FSH, LH and testosterone was maximally suppressed. The i.v. injection of 400 ng LHRH was totally ineffective at stimulating an increase in the blood concentrations of LH while the i.v. injection of 50 micrograms ovine LH induced a normal increase in the concentrations of testosterone; this confirmed that the chronic treatment with the LHRH agonist had desensitized the pituitary gonadotrophs without markedly affecting the responsiveness of the testicular Leydig cells. The ratio of bioactive: radioimmunoactive LH did not change during the treatment. The long-term effect of the infusion was fully reversible as shown by the increase in the blood concentrations of FSH, LH and testosterone and the return of normal pulsatile fluctuations in LH and testosterone within 7 days of the end of treatment.
成年索艾公羊使用皮下植入的渗透微型泵，每天注入50微克布舍瑞林，持续21天。用这种促性腺激素释放激素（LHRH）激动剂持续治疗，导致促黄体生成素（LH）（15倍）和睾酮（5倍）的血液浓度超生理水平升高，随后在10天后降至治疗前值以下。促卵泡生成素（FSH）的血液浓度仅在开始时有最小程度的升高，但随后在1天内急剧下降。到治疗第10天，所有3种激素的血液浓度都很低或在下降，基于20分钟血样的连续记录中没有LH脉冲，并且注射LHRH抗血清未能影响LH或睾酮的分泌。到第21天，FSH、LH和睾酮的分泌被最大程度地抑制。静脉注射400纳克LHRH在刺激LH血液浓度升高方面完全无效，而静脉注射50微克绵羊LH可使睾酮浓度正常升高；这证实了用LHRH激动剂进行慢性治疗使垂体促性腺细胞脱敏，而没有明显影响睾丸间质细胞的反应性。在治疗期间，生物活性LH与放射免疫活性LH的比例没有变化。治疗结束后7天内，FSH、LH和睾酮的血液浓度升高，LH和睾酮恢复正常的脉冲波动，这表明输注的长期影响是完全可逆的。
