Jeandel L, Van Dorsselaer A, Lutz-Bucher B, Koch B
Neuroendocrinology. 1987 Feb;45(2):146-51. doi: 10.1159/000124716.
The present study attempts to determine whether part of the corticotropin-releasing factor (CRF)-like materials present in the 'posterior pituitary' is composed of authentic CRF and examines whether the concentration of that peptide may be modulated by circulating glucocorticoids. Analysis of crude extracts of neurointermediate lobes (NIL) of rat pituitaries by reverse-phase HPLC, coupled with a specific radioimmunoassay (RIA), revealed the presence of a major component eluting with the same retention time as rat CRF (rCRF) and, importantly, which was indistinguishable by RIA from the synthetic peptide. Also, two minor forms eluted earlier than rCRF upon HPLC; one of these forms matched the elution position of r[Met(O)21,38]CRF. All three species did show biological activity and stimulated ACTH release from pituitary cells. Essentially the same elution profile was generated by median eminence (ME) extracts. Immunoreactive CRF (CRFi) content of the NIL was about 3% of that of the ME and was found to undergo a significant increase as a result of long-term adrenalectomy while, in contrast, CRFi content of the ME was decreased. This effect of adrenalectomy was completely antagonized by dexamethasone treatment. This study thus provides strong evidence for the presence of authentic CRF within the NIL of the rat pituitary and also shows that tissue concentration of that peptide was modulated by glucocorticoids.
本研究试图确定存在于“垂体后叶”中的部分促肾上腺皮质激素释放因子（CRF）样物质是否由真正的CRF组成，并研究该肽的浓度是否可被循环糖皮质激素调节。通过反相高效液相色谱（HPLC）结合特异性放射免疫测定（RIA）对大鼠垂体神经中间叶（NIL）的粗提物进行分析，结果显示存在一种主要成分，其洗脱保留时间与大鼠CRF（rCRF）相同，重要的是，通过RIA检测，该成分与合成肽无法区分。此外，在HPLC上有两种次要形式的洗脱时间比rCRF早；其中一种形式与r[Met（O）21,38]CRF的洗脱位置匹配。所有这三种物质均显示出生物活性，并能刺激垂体细胞释放促肾上腺皮质激素（ACTH）。正中隆起（ME）提取物产生的洗脱图谱基本相同。NIL中免疫反应性CRF（CRFi）的含量约为ME的3%，并且发现长期肾上腺切除术后其含量显著增加，而相比之下，ME中的CRFi含量则降低。地塞米松治疗完全拮抗了肾上腺切除术的这种作用。因此，本研究为大鼠垂体NIL中存在真正的CRF提供了有力证据，并且还表明该肽的组织浓度受糖皮质激素调节。
