Purswell B J, Wilcke J R
Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg 24061.
J Reprod Fertil Suppl. 1993;47:335-41.
In Expt 1, gonadotropin-releasing hormone (GnRH) (Cystorelin, CEVA) was administered intramuscularly to two intact male dogs; one dog received one injection of 50 micrograms GnRH and one dog received four daily injections of 50 micrograms GnRH. Both dogs exhibited a significant and immediate rise in luteinizing hormone (LH) following GnRH administration, with a peak observed at 15 min following injection. Testosterone was increased over baseline concentrations for 5 and 7 days, respectively, after the injection. In Expt 2, eight intact male dogs were injected intramuscularly with 0.7 microgram GnRH (Factrel, Fort Dodge) kg-1. Baseline testosterone concentrations were established by daily sampling for 14 days before treatment. All dogs exhibited an LH peak 15 min and a testosterone peak 60 min after the GnRH injection. Testosterone concentrations had returned to baseline concentrations by 4 h after the injection. Testosterone tended to fall below baseline concentrations for several days following the injection of GnRH. No peak was noted for follicle-stimulating hormone. In Expt 3, five additional dogs were injected with 0.7 microgram GnRH (Factrel, Fort Dodge) kg-1. Testosterone concentrations rose in all dogs 1 h after the injection and returned to baseline concentrations by 24 h after injection. In the male dog, GnRH stimulated an LH peak 15 min and a testosterone peak 1 h after injection. Further investigations are needed to elucidate the different effects on testosterone concentration observed with two different GnRH preparations.
在实验1中，向两只未阉割的雄性犬肌肉注射促性腺激素释放激素（GnRH）（赛斯灵，CEVA）；一只犬接受一次50微克GnRH注射，另一只犬每天接受4次50微克GnRH注射。两只犬在注射GnRH后促黄体生成素（LH）均立即显著升高，注射后15分钟出现峰值。注射后，睾酮分别在5天和7天内高于基线浓度。在实验2中，8只未阉割的雄性犬按每千克体重0.7微克GnRH（法克瑞，福道奇）进行肌肉注射。在治疗前通过每天采样14天来确定基线睾酮浓度。所有犬在注射GnRH后15分钟出现LH峰值，60分钟出现睾酮峰值。注射后4小时，睾酮浓度恢复到基线浓度。注射GnRH后几天，睾酮浓度往往低于基线浓度。未观察到促卵泡激素峰值。在实验3中，另外5只犬按每千克体重0.7微克GnRH（法克瑞，福道奇）进行注射。所有犬在注射后1小时睾酮浓度升高，注射后24小时恢复到基线浓度。在雄性犬中，GnRH注射后15分钟刺激LH峰值出现，1小时后刺激睾酮峰值出现。需要进一步研究以阐明两种不同GnRH制剂对睾酮浓度观察到的不同影响。
