The research will determine which structural features of certain hormones can be related to their biological activities. The hormones to be studied are prolactin (PRL), and growth hormone (GH), and the related protein placental lactogen. Fragments of the hormones will prepared by chemical and enzymatic cleavage and they will be tested for receptor binding activity using membrane preparations from various organs. The same question will be addressed using a different approach. Segments of these hormones that are thought to be of functional significance will be detected using the techniques of site specific mutagenesis. In addition, the amino acids in such segments of one kind of hormone (e.g. a PRL) will be replaced by he amino acids in the same segment of the other kind of hormone (i.e. GH). The mutant molecules will then be tested for receptor binding and biological activities. These hormones are involved in both normal and abnormal growth. Information on their structural features will be of value in producing analogue that can block their action or that have enhanced biological activities.
