The objectives of this research proposal is to develop antibodies capable of distinguishing normal human growth hormone (hGH-N) from the product of the variant growth hormone gene (hGH-V). Peptides will be synthesized corresponding to regions of dis- similarity from both forms of the hormone. These peptides will then be conjugated to carrier molecules for synthesis of effective immunogens and used to generate specific antibodies in rabbits. These antibodies will be tested for specificity of binding to one form of the hormone or the other. Such antibodies should be useful to determine whether or not the variant gene is expressed in humans. Immunoassays utilizing these hormones should have extensive utility in diagnosis of growth disorders in humans.