GHSR and metabolic disease: Future opportunities for GHSR1a research are four-fold: (1) to define the mechanism underlying the tissue specific response in GHSR1a-mediated intracellular signaling; (2) to examine the tissue specificity of GHSR1a constitutive activity and ligand-induced response and their physiological relevance; (3) to explore the integrative function of GHSR1a in the intricate regulatory network governing energy metabolism and metabolic homeostasis; (4) to evaluate the potential applications of GHSR1a agonists, antagonists or inverse agonist in the treatment of obesity and its related metabolic diseases.