Its primary function is the prevention of hypercalcemia. Upon release into the circulation, it lowers calcium transport by the gills, thereby reducing its rate of influx from the environment into the extracellular compartment. STC also stimulates phosphate reabsorption by renal proximal tubules. The consequence of this action is increased levels of plasma phosphate, which combines with excess calcium and promotes its disposal into bone and scales. Homodimer; disulfide-linked. Corpuscles of Stannius. Belongs to the stanniocalcin family.