Abstract: The present invention provides that an endogenous opioid peptide, OGF, inhibits angiogenesis in vivo via acting on OGF receptor. The present inventions also provides that opioid antagonist naltrexone and naltrexone stimulated blood vessel development. Therapeutic compositions and methods for modulating angiogenesis are provided.

Abstract: The present invention is related to the treatment and prevention of cancer including particularly gastrointestinal cancer. More specifically, the present invention describes the use of naltrexone, naloxone and the pentapeptide growth factor [Met.sup.5 ]-enkephalin to inhibit and arrest the growth of cancer. Such efficiency has been discovered to be a consequence of the functional manipulation of the zeta (.zeta.) opioid receptor through endogenous [Met.sup.5 ]-enkephalin. This receptor has been determined to be present in growing cancers such as pancreatic and colon cancer, for example.

Abstract: A method for regulating the growth processes in a myriad of cells, tissues, organ systems and unicellular and multicellular organisms including plants, animals and man by the administration of effective amounts of the opioid antagonists naloxone, naltrexone, their analogs, metabolites derivatives, and/or mixtures thereof. At the cellular level, the growth processes entail all mitetic events and related processes including cell proliferation, as well as cell migration and cell differentiation, and at the somatic or organismal level, anatomical, behavioral and neurological development, metamorphisis and maturation. Growth regulation can be effected in vivo and/or in vitro.

Abstract: A method for regulating the growth processes in a myriad of cells, tissues, organ systems and unicellular and multicellular organisms including plants, animals and man by the administration of effective amounts of the opioid antagonists naloxone, naltrexone, their analogs, metabolites derivatives, and/or mixtures thereof. At the cellular level, the growth processes entail all mitotic events and related processes including cell proliferation, as well as cell migration and cell differentiation, and at the somatic or organismal level, anatomical, behavioral and neurological development, metamorphisis and maturation. Growth regulation can be effected in vivo and/or in vitro.

Abstract: A method for regulating the growth processes in a myriad of cells, tissues, organ systems and unicellular and multicellular organisms including plants, animals and man by the administration of effective amounts of the opioid antagonists naloxone, naltrexone, their analogs metabolites derivatives, and/or mixtures thereof. At the cellular level, the growth processes entail all mitotic events and related processes including cell proliferation, as well as cell migration and cell differentiation, and at the somatic or organismal level, anatomical, behavioral and neurological development, metamorphisis and maturation. Growth regulation can be effected in vivo and/or in vitro.