One of the major objectives will be isolation and characterization of the growth factor (PGF) produced by plerocercoids of the tapeworm, Spirometra mansonoides. Procedures for initial step of purification have been established and attempts will be made to sensitize appropriate animals to make specific antibodies directed against PGF. Steps will be taken to increase the numbers of plerocercoids available so that preparative fractionation procedures may be undertaken. Once PGF is purified in sufficient quantities the primary, secondary and tertiary structure of the molecule will be determined. A second objective will be to determine the effects of PGF in hypophysectomized monkeys in short term as well as extended studies. If PGF stimulates growth in monkeys, it is highly conceivable that it will be active in humans. A third objective will be to determine the effect of PGF on metabolism and how these effects relate to other growth factors, such as growth hormone, somatomedin, insulin, glucagon and thyroid hormone. A fourth objective will be to determine what direct effects PGF has in isolated tissue preparations.