PTH and osteoporosis: Disruption in this coupling in osteoporosis is mediated by a multifaceted interplay of biomolecules including, but not limited to cytokines (such as RANKL, OPG, and interleukins), growth factors (e.g., TGF-β and IGF-1), and hormones (including estrogen, testosterone, and parathyroid hormone) (3).