Schwartz J, Penke B, Rivier J, Vale W
Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037.
Endocrinology. 1987 Oct;121(4):1454-60. doi: 10.1210/endo-121-4-1454.
To develop a cytotoxic agent selective for pituitary corticotropes, an analog of CRF, [Nle21,38,Arg36]rat (r) CRF, was conjugated to the plant toxin gelonin using glutaraldehyde as a cross-linking agent. In a two-step synthesis, glutaraldehyde was first coupled to the amino-terminal of the CRF analog. This was then reacted with gelonin to form a product, which contained 20 mol [Nle21,38,Arg36]rCRF/mol gelonin, as indicated by amino acid analysis. Efficacy and specificity of the gelonin-[Nle21,38,Arg36]rCRF conjugate were assessed in cultured rat anterior pituitary cells 3 days after a 12-h exposure to the cytotoxic conjugate, CRF, or gelonin. While pretreatment with the cytotoxic gelonin-[Nle21,38,Arg36]rCRF conjugate decreased cellular ACTH content by 74%, pretreatment with appropriate concentrations of CRF had no significant effect on cellular ACTH content. The ACTH secretory response to 2.5 nM CRF was completely eliminated by pretreatment with the gelonin-[Nle21,38,Arg36]rCRF conjugate; in contrast, pretreatment with identical doses of CRF had minimal effect. Neither pretreatment with CRF nor pretreatment with the gelonin-[Nle21,38,Arg36] rCRF conjugate had any effect on the content of LH or the LH secretory response to GnRH. These results indicate the efficacy and specificity of the conjugate of [Nle21,38,Arg36]rCRF to gelonin in eliminating CRF target cells.
为研发一种对垂体促肾上腺皮质激素细胞具有选择性的细胞毒性药物，促肾上腺皮质激素释放因子（CRF）的类似物[Nle21,38,Arg36]大鼠（r）CRF，以戊二醛作为交联剂，与植物毒素相思豆毒素进行偶联。在两步合成过程中，戊二醛首先与CRF类似物的氨基末端偶联。然后使其与相思豆毒素反应形成一种产物，氨基酸分析表明，该产物含有20摩尔的[Nle21,38,Arg36]rCRF/摩尔相思豆毒素。在对细胞毒性偶联物、CRF或相思豆毒素进行12小时暴露后3天，在培养的大鼠垂体前叶细胞中评估相思豆毒素-[Nle21,38,Arg36]rCRF偶联物的疗效和特异性。虽然用细胞毒性的相思豆毒素-[Nle21,38,Arg36]rCRF偶联物预处理可使细胞促肾上腺皮质激素（ACTH）含量降低74%，但用适当浓度的CRF预处理对细胞ACTH含量无显著影响。用相思豆毒素-[Nle21,38,Arg36]rCRF偶联物预处理可完全消除对2.5 nM CRF的ACTH分泌反应；相比之下，用相同剂量的CRF预处理影响极小。用CRF预处理或用相思豆毒素-[Nle21,38,Arg36]rCRF偶联物预处理对促黄体生成素（LH）含量或LH对促性腺激素释放激素（GnRH）的分泌反应均无任何影响。这些结果表明[Nle21,38,Arg36]rCRF与相思豆毒素的偶联物在消除CRF靶细胞方面的疗效和特异性。
