Given that the production of soluble polypeptide hormone and cytokine receptors is regulated by alternative splicing, protease activation, secretion of membrane vesicles [31], ligand-mediated receptor activation [15] and stress [19], the higher concentrations of the sLHCGR/LH-sLHCGR that we have observed could be attributed to infection, endometriosis, ovarian and adrenal pathology, obesity, insulin resistance and other metabolic diseases. Here, PLOD1 is linked to obesity due to melanocortin 4 receptor deficiency.