Research Progress on Signal Transduction Mechanisms Underlying Growth Hormone Receptor Action

Growth hormone (GH) has important physiological roles on animals in growth and development. GH plays a series of physiological effects after binding to growth hormone receptor (GHR). Our understanding of the mechanisms of action of GH and its receptor, the GHR, has advanced significantly in the last decade and has provided some important surprises. It is now clear that the GH-GHR axis activates a number of inter-related signalling pathways, not all of which are dependent on the intracellular tyrosine kinase, JAK2 as originally postulated. This paper summarizes the following aspects of signal transduction mechanisms progress under the GHR role:GHR structure and function;GHR signalling including JAK2-dependent signalling and JAK2-independent signalling; negative regulators of GHR signalling. Continued emphasis on elucidation of these complex mechanisms is critical to provide further insights into the animal diverse physiological and pathophysiological effects of GH.