Hadley M E, Zechel C, Wilkes B C, Castrucci A M, Visconti M A, Pozo-Alonso M, Hruby V J
Life Sci. 1987 Mar 23;40(12):1139-45. doi: 10.1016/0024-3205(87)90231-1.
H-Asp-Thr-Met-Arg-Cys-Met-Val-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val-OH , melanin concentrating hormone (MCH), exhibits both melanin granule concentrating and dispersing (MSH-like) activities. Fragment analogues of MCH were synthesized as described herein and the melanotropic activities of the peptides were determined. In the frog (Rana pipiens) and lizard (Anolis carolinensis) skin bioassays, the 5-17 and 5-14 fragments of MCH were inactive (at concentrations of 10(-5)M or less), whereas the 1-14 sequence exhibited minimal (about 10%) MSH-like activity compared to MCH, which, as reported previously, was about 600 times less active than alpha-MSH. In the teleost (fish) skin bioassay, the MCH5-17 analogue was equipotent to MCH, whereas the 1-14 analogue was 10-30 times and the cyclic N- and C- terminal truncated analogue, MCH5-14, was about 300 times less active than MCH. These results suggest that the N-terminal sequence is particularly critical to MSH-like activity in the tetrapod species studied, whereas other structural regions of MCH, particularly in the C-terminal, are more related to MCH activity in teleosts.
H-天冬酰胺-苏氨酸-甲硫氨酸-精氨酸-半胱氨酸-甲硫氨酸-缬氨酸-甘氨酸-精氨酸-缬氨酸-酪氨酸-精氨酸-脯氨酸-半胱氨酸-色氨酸-谷氨酸-缬氨酸-OH，即黑色素聚集激素（MCH），兼具黑色素颗粒聚集和分散（促黑素细胞激素样）活性。如本文所述合成了MCH的片段类似物，并测定了这些肽的促黑素活性。在青蛙（豹蛙）和蜥蜴（卡罗来纳安乐蜥）皮肤生物测定中，MCH的5-17和5-14片段无活性（浓度为10⁻⁵M或更低），而1-14序列与MCH相比表现出最小的（约10%）促黑素细胞激素样活性，如先前报道，其活性比α-促黑素细胞激素低约600倍。在硬骨鱼皮肤生物测定中，MCH5-17类似物与MCH等效，而1-14类似物活性比MCH低10 - 30倍，环状N端和C端截短的类似物MCH5-14活性比MCH低约300倍。这些结果表明，在研究的四足动物物种中，N端序列对促黑素细胞激素样活性尤为关键，而MCH的其他结构区域，特别是C端，与硬骨鱼中的MCH活性更相关。
