title: The head activator is released from regenerating Hydra bound to a carrier molecule.
abstract: 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.
authors.affiliation: ZMBH, Zentrum für Molekulare Biologie, Im Neuenheimer Feld 282, 6900 Heidelberg, FRG.
authors.forename: H C
authors.initials: HC
authors.lastname: Schaller
authors.forename: M
authors.initials: M
authors.lastname: Roberge
authors.forename: B
authors.initials: B
authors.lastname: Zachmann
authors.forename: S
authors.initials: S
authors.lastname: Hoffmeister
authors.forename: E
authors.initials: E
authors.lastname: Schilling
authors.forename: H
authors.initials: H
authors.lastname: Bodenmüller