INS and Insulin resistance: It is suggested that 25-OH-D provides structural and functional support for pancreatic β cells and thus can be used for modulating insulin resistance and alleviating relevant immune responses.8 A reduction in serum 25-OH-D can trigger a shutdown of the Ca+ pathway on the pancreatic β-cell membrane, contributing to abnormal production and release of insulin by islet cells and worsening of insulin resistance.