Rivier J E, Kirby D A, Lahrichi S L, Corrigan A, Vale W W, Rivier C L
The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
J Med Chem. 1999 Aug 12;42(16):3175-82. doi: 10.1021/jm9902133.
In an earlier report we identified specific modifications and substitutions of corticotropin releasing factor (CRF) that led to the discovery of antagonists with extended duration of action as compared to that of astressin {cyclo(30-33)[DPhe(12),Nle(21),Glu(30), Lys(33),Nle(38)]hCRF((12)(-)(41))}. These additional modifications included elongation of the peptide chain by three residues at the N-terminus, its acetylation, and the [CalphaMeLeu(27)] substitution to yield cyclo(30-33)[DPhe(12), Nle(21),CalphaMeLeu(27),Glu(30), Lys(33),Nle(38)]Ac-hCRF((9)(-)(41)), which was found to be longer acting than astressin (Rivier, J.; et al. J. Med. Chem. 1998, 41, 5012-5019). To further increase the efficiency (potency, duration of action, and bioavailability) of this family of antagonists, we introduced two or more CalphaMe-leucine residues at positions shown in earlier studies to be favorable (Hernandez, J.-F.; et al. J. Med. Chem. 1993, 36, 2860-2867). Whereas the introduction of CalphaMe-leucine residues at positions 27 and either 18 (11), 37 (17), or 40 (19) resulted in dramatic increases in duration of inhibitory action in the adrenalectomized (adx) rat after intravenous injection, the same substitution at positions 27 and either 15 (7, 8), 17 (9), 19 (12, 13), or 41 (20) led to short acting analogues. Other substitutions by CalphaMeLeu at positions 27 and either 10 (4), 13 (5), 14 (6), 21 (14), 24 (15), 36 (16), or 38 (18) yielded analogues with duration of action intermediate between those mentioned above. Cyclo(30-33)[DPhe(12), Nle(21), CalphaMeLeu(27),Glu(30),Lys(33),Nle(38), CalphaMeLeu(40)]Ac-hCRF((9)(-)(41)) (astressin B, 19) was one of the most efficacious analogues of this series (>4 h inhibition of ACTH secretion at 25 microgram/adx rat). It was found to be even longer acting via subcutaneous administration in either an aqueous (>24 h inhibition of ACTH secretion at 100 microgram/adx rat) or lipid milieu (DMSO/peanut oil, >24 h inhibition of ACTH secretion at 30 microgram/adx rat) than after intravenous administration (<12 h inhibition of ACTH secretion at 100 microgram/adx rat). We concluded that Calpha-methylation at some positions may favor a bioactive conformation while also preventing degradation and/or elimination, resulting in significant extension of duration of action.
在较早的一份报告中,我们确定了促肾上腺皮质激素释放因子(CRF)的特定修饰和取代,这导致了与阿斯特辛{环(30 - 33)[D - 苯丙氨酸(12),正亮氨酸(21),谷氨酸(30),赖氨酸(33),正亮氨酸(38)]人CRF((12)( - )(41))}相比作用持续时间延长的拮抗剂的发现。这些额外的修饰包括在N端将肽链延长三个残基、其乙酰化以及[α - 甲基亮氨酸(27)]取代,从而产生环(30 - 33)[D - 苯丙氨酸(12),正亮氨酸(21),α - 甲基亮氨酸(27),谷氨酸(30),赖氨酸(33),正亮氨酸(38)]乙酰 - hCRF((9)( - )(41)),发现其作用时间比阿斯特辛更长(里维尔,J.;等人,《药物化学杂志》,1998年,41卷,5012 - 5019页)。为了进一步提高该类拮抗剂的效率(效力、作用持续时间和生物利用度),我们在早期研究显示有利的位置引入了两个或更多的α - 甲基亮氨酸残基(埃尔南德斯,J.-F.;等人,《药物化学杂志》,1993年,36卷,2860 - 2867页)。虽然在位置27和18(11)、37(17)或40(19)引入α - 甲基亮氨酸残基会导致静脉注射后去肾上腺(adx)大鼠的抑制作用持续时间显著增加,但在位置27和15(7, 8)、17(9)、19(12, 13)或41(20)进行相同取代会产生短效类似物。在位置27和10(4)、13(5)、14(6)、21(14)、24(15)、36(16)或38(18)进行α - 甲基亮氨酸的其他取代产生的类似物,其作用持续时间介于上述两者之间。环(30 - 33)[D - 苯丙氨酸(12),正亮氨酸(21),α - 甲基亮氨酸(27),谷氨酸(30),赖氨酸(33),正亮氨酸(38),α - 甲基亮氨酸(40)]乙酰 - hCRF((9)( - )(41))(阿斯特辛B,19)是该系列中最有效的类似物之一(在25微克/去肾上腺大鼠时对促肾上腺皮质激素分泌的抑制>4小时)。发现通过皮下给药,无论是在水性介质(在100微克/去肾上腺大鼠时对促肾上腺皮质激素分泌的抑制>24小时)还是脂质环境(二甲基亚砜/花生油,在30微克/去肾上腺大鼠时对促肾上腺皮质激素分泌的抑制>24小时)中,其作用持续时间都比静脉给药(在100微克/去肾上腺大鼠时对促肾上腺皮质激素分泌的抑制<12小时)更长。我们得出结论,在某些位置的α - 甲基化可能有利于生物活性构象,同时还能防止降解和/或消除,从而显著延长作用持续时间。