Keel B A, Schanbacher B D, Grotjan H E
Biol Reprod. 1987 Jun;36(5):1102-13. doi: 10.1095/biolreprod36.5.1102.
Chromatofocusing was used to separate and characterize the isohormones of ovine luteinizing hormone (oLH) in the pituitaries of rams, wethers, and wethers receiving Silastic implants containing 5 alpha-dihydrotestosterone (DHT), 17 beta-estradiol (E2), or DHT plus E2. Extracts of anterior pituitaries were prepared by homogenization and centrifugation at 100,000 X g. Castration reduced the amount of oLH in the pituitary, even though peripheral levels were elevated. Pituitary oLH concentrations in wethers were further reduced by all three steroid treatments. When subjected to chromatofocusing on pH 10.5 to 7.0 gradients, pituitary extracts yielded eight peaks of immunoreactive oLH, which eluted with apparent isoelectric points of greater than 9.8, 9.26, 9.14, 9.07, 8.98, 8.91, and less than or equal to 7.0. These isohormones were designated A-G and Z, respectively. In rams, isohormones F and G were the predominant species, representing approximately equal to 57% of the immunoreactive oLH recovered from the column. Castration resulted in a subtle shift toward more basic isohormones. DHT administration caused an increase in the relative amount of isohormone A, whereas E2 treatment resulted in an increase in isohormone Z. DHT and E2 in combination produced increases in the relative amounts of both isohormones A and Z. All eight oLH isohormones were active in an in vitro LH bioassay and exhibited biological-to-immunological-assay (B/I) ratios in the ram ranging from 0.4 to 2.8. Isohormone F exhibited the highest B/I ratio in all the treatment groups. Similarly, isohormone F was clearly the predominant biologically active form of oLH in all groups. These results demonstrate that at least eight immunoreactive and biologically active forms of pituitary oLH can be separated by using chromatofocusing; the pattern of oLH isohormones is markedly different from that in the rat; castration has a minimal effect on the pattern of oLH isohormones in pituitary extracts; and exogenous gonadal steroid administration reduces the amount of oLH in the pituitary and changes the pattern of oLH isohormones, resulting in a higher percentage of less biologically active forms.
采用色谱聚焦法分离并鉴定了公羊、去势公羊以及接受含5α - 双氢睾酮（DHT）、17β - 雌二醇（E2）或DHT加E2的硅橡胶植入物的去势公羊垂体中绵羊促黄体生成素（oLH）的同激素。通过匀浆和100,000×g离心制备垂体前叶提取物。去势降低了垂体中oLH的含量，尽管外周水平升高。三种类固醇处理均进一步降低了去势公羊垂体中的oLH浓度。当在pH 10.5至7.0梯度上进行色谱聚焦时，垂体提取物产生了8个免疫反应性oLH峰，其洗脱时的表观等电点大于9.8、9.26、9.14、9.07、8.98、8.91以及小于或等于7.0。这些同激素分别被命名为A - G和Z。在公羊中，同激素F和G是主要类型，约占从柱上回收的免疫反应性oLH的57%。去势导致向更碱性的同激素有轻微转变。给予DHT导致同激素A的相对量增加，而E2处理导致同激素Z增加。DHT和E2联合使用使同激素A和Z的相对量均增加。所有8种oLH同激素在体外LH生物测定中均有活性，在公羊中生物测定与免疫测定（B/I）比值范围为0.4至2.8。同激素F在所有处理组中表现出最高的B/I比值。同样，同激素F显然是所有组中oLH的主要生物活性形式。这些结果表明，使用色谱聚焦法可分离出至少8种免疫反应性和生物活性形式的垂体oLH；oLH同激素模式与大鼠明显不同；去势对垂体提取物中oLH同激素模式影响极小；外源性性腺类固醇给药降低了垂体中oLH的含量并改变了oLH同激素模式，导致生物活性较低的形式所占百分比更高。
