Schwartz J, Vale W
Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037.
Endocrinology. 1988 Apr;122(4):1695-700. doi: 10.1210/endo-122-4-1695.
Control of ACTH secretion in the pituitary in the absence of target cells for CRF, the most potent ACTH secretagogue, was studied in dissociated bovine anterior pituitary cells treated with a potent selective cytotoxin. The cytotoxin is a conjugate of the CRF analog [Nle21,38, Arg36]rat (r) CRF and the plant toxin gelonin. Dissociated bovine anterior pituitary cells were pretreated with vehicle, 2 nM ovine CRF, 2 nM cytotoxic conjugate, or unconjugated [Nle21,38,Arg36]rCRF and gelonin in amounts equivalent to that of 2 nM cytotoxic conjugate for 12 h, then extensively washed and cultured for 3 days before acute secretion experiments. Unstimulated ACTH secretion was similar in all groups. ACTH secretion in response to CRF was attenuated by pretreatment with the cytotoxic conjugate; CRF (2.5 nM)-stimulated secretion was 7.0, 6.3, and 2.8 times the unstimulated rate in cells pretreated with vehicle, 2 nM CRF, or 2 nM cytotoxic conjugate, respectively. Likewise, the ACTH secretory response to a cAMP analog was attenuated by pretreatment with the conjugate; 8-bromo-cAMP (10 mM)-stimulated secretion was 6.8, 7.1, and 3.3 times the unstimulated rate in cells pretreated with vehicle, CRF, or conjugate, respectively. In contrast, the ACTH responses to vasopressin (VP) or oxytocin (OR) remained intact. VP stimulated the ACTH secretion rate by 4.2, 4.0, and 3.5 times, respectively, in the three groups. OT stimulated the ACTH secretion rate by 2.7, 2.6, and 2.3 times in the three groups. Pretreatment with the conjugate attenuated the response to CRF and VP in combination by the same amount as it attenuated the response to CRF alone. The ACTH secretory responses in cells pretreated with unconjugated [Nle21,38,Arg36]rCRF and gelonin were not different from responses in cells pretreated with vehicle. These results suggest that there is a separate mechanism or cell type for OT- and VP-stimulated ACTH secretion distinct from that responsible for the action of CRF on pituitary cells.
在缺乏促肾上腺皮质激素释放因子（CRF，最有效的促肾上腺皮质激素促分泌素）靶细胞的情况下，研究了用一种强效选择性细胞毒素处理的离体牛垂体前叶细胞中促肾上腺皮质激素（ACTH）分泌的控制。该细胞毒素是CRF类似物[Nle21,38,Arg36]大鼠（r）CRF与植物毒素鹅膏蕈碱的偶联物。将离体牛垂体前叶细胞用溶剂、2 nM绵羊CRF、2 nM细胞毒性偶联物或与2 nM细胞毒性偶联物等量的未偶联[Nle21,38,Arg36]rCRF和鹅膏蕈碱预处理12小时，然后充分洗涤并培养3天，再进行急性分泌实验。所有组中未刺激的ACTH分泌相似。用细胞毒性偶联物预处理可减弱对CRF的ACTH分泌反应；CRF（2.5 nM）刺激的分泌分别是用溶剂、2 nM CRF或2 nM细胞毒性偶联物预处理的细胞中未刺激分泌率的7.0、6.3和2.8倍。同样，用偶联物预处理可减弱对cAMP类似物的ACTH分泌反应；8-溴-cAMP（10 mM）刺激的分泌分别是用溶剂、CRF或偶联物预处理的细胞中未刺激分泌率的6.8、7.1和3.3倍。相反，对血管加压素（VP）或催产素（OT）的ACTH反应保持完整。在三组中，VP分别将ACTH分泌率提高了4.2、4.0和3.5倍。OT在三组中分别将ACTH分泌率提高了2.7、2.6和2.3倍。用偶联物预处理减弱对CRF和VP联合反应的程度与减弱对单独CRF反应的程度相同。用未偶联的[Nle21,38,Arg36]rCRF和鹅膏蕈碱预处理的细胞中的ACTH分泌反应与用溶剂预处理的细胞中的反应无差异。这些结果表明，OT和VP刺激ACTH分泌存在一种独立于CRF对垂体细胞作用的机制或细胞类型。
