Stewart B L, Roser J F
Department of Animal Science, University of California, Davis 95616, USA.
Domest Anim Endocrinol. 1998 Mar;15(2):129-39. doi: 10.1016/s0739-7240(97)00083-0.
The nature of the relationship between inhibin and reproductive function in the stallion is yet to be elucidated. Blood and testes from 51 light horse stallions ranging in age from 2 mo to 25 years were collected during the breeding and nonbreeding seasons to study the effects of testicular maturation, aging, season, and fertility status on peripheral and intratesticular concentrations of Ir inhibin and other reproductive hormones. Of the 51 stallions, 12 age-matched stallions (6 fertile, 3 subfertile, and 3 infertile) were used in the fertility study. Blood samples were taken before castration and plasma stored at -20 degrees C for analysis of Ir inhibin, luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estradiol (E2), and estrogen conjugates (EC) by radioimmunoassay (RIA). Testes were homogenized and testicular extracts prepared and frozen at -70 degrees C for analysis of Ir inhibin, T, E2, and EC by RIA. Plasma concentrations of Ir inhibin, LH, FSH, T, E2, and EC and intratesticular concentrations of Ir inhibin, T, E2, and EC increased with age (P < 0.01). The most dramatic effect appeared to be during testicular maturation. An aging effect was not observed in adult stallions. A seasonal effect was not detected for any of the plasma hormones, whereas for the intratesticular hormones the only change noted was an increase in T in the nonbreeding season (P < 0.05). Plasma Ir inhibin, E2, and EC were lower (P < 0.01) and gonadotropins higher (P < 0.05) in infertile stallions. Plasma T levels did not change. Intratesticular Ir inhibin concentrations tended to be lower (P < 0.1) in subfertile stallions and significantly lower (P < 0.01) in infertile stallions, whereas intratesticular steroid levels were not different among the three groups. In conclusion, plasma and intratesticular Ir inhibin concentrations seem to be affected by testicular maturation and fertility status.
抑制素与种马生殖功能之间关系的本质尚待阐明。在繁殖季节和非繁殖季节收集了51匹年龄从2个月到25岁的轻型马种马的血液和睾丸，以研究睾丸成熟、衰老、季节和生育状态对外周血和睾丸内抑制素免疫反应性（Ir）以及其他生殖激素浓度的影响。在51匹种马中，12匹年龄匹配的种马（6匹可育、3匹亚可育和3匹不育）用于生育力研究。在阉割前采集血样，血浆储存在-20℃，通过放射免疫测定法（RIA）分析抑制素免疫反应性、促黄体生成素（LH）、促卵泡激素（FSH）、睾酮（T）、雌二醇（E2）和雌激素结合物（EC）。将睾丸匀浆并制备睾丸提取物，冷冻保存在-70℃，通过RIA分析抑制素免疫反应性、睾酮、雌二醇和雌激素结合物。外周血中抑制素免疫反应性、促黄体生成素、促卵泡激素、睾酮、雌二醇和雌激素结合物以及睾丸内抑制素免疫反应性、睾酮、雌二醇和雌激素结合物的浓度随年龄增长而升高（P<0.01）。最显著的影响似乎发生在睾丸成熟期间。在成年种马中未观察到衰老效应。未检测到任何外周血激素的季节性效应，而对于睾丸内激素，唯一观察到的变化是在非繁殖季节睾酮升高（P<0.05）。不育种马的外周血抑制素免疫反应性、雌二醇和雌激素结合物较低（P<0.01），促性腺激素较高（P<0.05）。外周血睾酮水平未发生变化。亚可育种马的睾丸内抑制素免疫反应性浓度趋于较低（P<0.1），不育种马显著较低（P<0.01），而三组之间睾丸内类固醇水平无差异。总之,外周血和睾丸内抑制素免疫反应性浓度似乎受睾丸成熟和生育状态的影响。
