Boyle M S, Skidmore J, Zhang J, Cox J E
Thoroughbred Breeders' Association Equine Fertility Unit, Newmarket, Suffolk.
J Reprod Fertil Suppl. 1991;44:169-82.
The effect of long-term treatment of stallions with a powerful gonadotrophin-releasing hormone (GnRH) analogue was investigated. In the first part of the study, 9 sexually mature pony stallions were allocated to 1 of 3 groups, each of which was treated with 240 micrograms or 60 micrograms Buserelin per day administered by subcutaneously sited osmotic pumps or 30-50 micrograms Buserelin per day via solid, slow-release implants injected subcutaneously. Peripheral blood plasma and serum samples were collected frequently and assayed for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and testosterone. No significant differences were seen between either high of low dose rates: in all treatment groups, serum and plasma concentrations of FSH, LH and testosterone rose sharply following insertion of pumps ofr implant. The levels remained elevated for 3-10 days in most animals, after which they returned to pre-treatment of lower values. In a second experiment, single implants, formulated to deliver 120 micrograms Buserelin per day for 28 days, were injected subcutaneously in to 2 pony stallions on 4 occasions at 5-day intervals. Gonadotrophin and testosterone secretions were temporarily stimulated in response to the first implant, but thereafter returned to pre-treatment or lower levels and showed no further stimulation following injection of subsequent implants. In a third experiment designed to establish the effects on libido and spermatogenesis of chronic treatment with levels of Buserelin (shown previously to depress gonadotrophin concentrations in stallions), 3 fertile pony stallions received subcutaneous implants at 2- to 5-week intervals for 12 months. Three untreated pony stallions acted as controls. Weekly blood samples were collected from both groups to monitor levels of FSH, LH, testosterone and oestrone sulphate. Semen was collected daily for 6-10 days both before treatment and at 3-month intervals thereafter in order to establish daily sperm output (DSO) and assess libido. Gonadotrophin, testosterone and oestrone sulphate levels were all lower in the treated group compared with either pre-treatment or control values. DSO was reduced by at least 50% throughout the treatment period in treated stallions but 7 months after insertion of the last implant it had returned to pre-treatment values. No significant effects on other semen characteristics were noted and there were no noticeable changes in libido of treated animals throughout the period of the experiment.
研究了用一种强效促性腺激素释放激素（GnRH）类似物对种马进行长期治疗的效果。在研究的第一部分，将9匹性成熟的小马种马分配到3组中的1组，每组分别通过皮下植入渗透泵每天给予240微克或60微克布舍瑞林，或通过皮下注射固体缓释植入剂每天给予30 - 50微克布舍瑞林。频繁采集外周血浆和血清样本，检测促卵泡激素（FSH）、促黄体生成素（LH）和睾酮。高剂量率和低剂量率之间未见显著差异：在所有治疗组中，植入泵或植入剂后，血清和血浆中FSH、LH和睾酮的浓度急剧上升。大多数动物的这些水平在3 - 10天内保持升高，之后又恢复到治疗前或更低的值。在第二个实验中，将设计为每天释放120微克布舍瑞林持续28天的单个植入剂，以5天间隔分4次皮下注射到2匹小马种马体内。第一次植入后，促性腺激素和睾酮分泌受到暂时刺激，但此后又恢复到治疗前或更低水平，后续植入注射后未显示进一步刺激。在第三个实验中，为确定布舍瑞林水平（先前显示可降低种马促性腺激素浓度）的长期治疗对性欲和精子发生的影响，3匹可育小马种马每隔2至5周接受皮下植入剂，持续12个月。3匹未治疗的小马种马作为对照。两组每周采集血样以监测FSH、LH、睾酮和硫酸雌酮水平。在治疗前以及此后每隔3个月，每天采集精液6 - 10天，以确定每日精子产量（DSO）并评估性欲。与治疗前或对照值相比，治疗组的促性腺激素、睾酮和硫酸雌酮水平均较低。治疗期间，治疗组种马的DSO至少降低了50%，但在最后一次植入后7个月，DSO又恢复到治疗前值。未观察到对其他精液特征有显著影响，且在整个实验期间治疗动物的性欲无明显变化。
