Recombinant Analogues of Prolactin, Growth Hormone, and Placental Lactogen: Correlations Between Physical Structure, Binding Characteristics, and Activity

The availability of recombinant growth hormones, prolactins, placental lactogens and a few soluble extracellular domains of their receptors have extended our ability to study the interaction of somatogenic and lactogenic hormones with their receptors. Modifications of their respective cDNAs have enabled the preparation of sufficient amounts of the corresponding proteins. The present review summarizes two aspects of these interactions: (a) the relationship between binding, the apparent ability to dimerize the receptors and biological activities in vitro and in vivo; and (b) the effect of mutations on selective changes in the ability of human growth hormone and bovine placental lactogen to interact with somatogenic and lactogenic receptors. In view of this summary, strategies for preparing a second generation of biologically relevant recombinant hormones are discussed.