Molecular model of growth hormone (GH) and its receptor (GHR), ribbon diagram/CPK model. Representation of the general architecture of the 1:2 complex (PDB code:3hhr). The two GHR mols. are shown as CPK models. GH elicitis a variety of biological activities mainly mediated by the GHR. GH binds to two receptors mols., thereby inducing signal transduction through receptor dimerization. GH, secreted from the anterior pituitary lobe, has multiple effects on growth, metabolism and the immune system.