Figure 3

Classical ligand-receptor relationships in rat and mouse, ovine and bovine, and human species. Arrows denote stimulatory actions; lines without arrows reflect inhibitory actions. Abbreviations: PRL, prolactin; PL-Is, placental lactogen-Iα, β, γ, and PL-I variant; PL-II, placental lactogen-II; GH, growth hormone; PL, placental lactogen; CSs, chorionic somatomammotropins; GH-V, growth hormone variant; PRL-R, PRL receptor; GH-R, GH receptor; PRL-R/GH-R, PRL-R and GH-R heterodimer.