ZMBH, Zentrum für Molekulare Biologie, Im Neuenheimer Feld 282, 6900 Heidelberg, FRG.
EMBO J. 1986 Aug;5(8):1821-4. doi: 10.1002/j.1460-2075.1986.tb04432.x.
Hydra forced to regenerate a head releases head activator and head inhibitor during the first hours after cutting to induce head-specific growth and differentiation processes. Analysis of the size distribution demonstrated that the head-activator peptide is co-released with (a) large molecular weight carrier molecule(s) to which it is non-covalently bound. The carrier-bound head activator is fully active on Hydra indicating that a carrier does not hinder the interaction with receptors. In contrast to this the head inhibitor is released in its naked, low molecular mass form. The association or non-association with a carrier molecule results in marked differences in biological properties. The head activator has a short range of action, but a long half-life, the head inhibitor has a global range of action, but a short half-life. These results provide a plausible explanation why two antagonistically acting substances, although they are released from the same site and simultaneously nevertheless can give rise to a well-defined temporal and spatial pattern of differentiation as occurs, for example, during head regeneration in Hydra.
水螅在切割后最初几小时内被迫再生头部时会释放头部激活剂和头部抑制剂，以诱导头部特异性生长和分化过程。大小分布分析表明，头部激活肽与（一种或多种）与之非共价结合的大分子量载体分子共同释放。带有载体的头部激活剂对水螅完全有效，表明载体不会阻碍与受体的相互作用。相比之下，头部抑制剂以其裸露的低分子量形式释放。与载体分子的结合或不结合导致生物学特性的显著差异。头部激活剂作用范围短，但半衰期长，头部抑制剂作用范围广，但半衰期短。这些结果提供了一个合理的解释，为什么两种拮抗作用的物质尽管从同一部位释放且同时释放，但仍能产生明确的时空分化模式，例如在水螅头部再生过程中发生的那样。
