In another study in parathyroidectomized rats, hypocalcemia induced by a low-calcium diet and hypercalcemia induced by infusion of Ca2+ decreased and increased, respectively, the levels of FGF23, together with opposite changes in the circulating active vitamin D levels, probably attenuating the real effect of Ca2+ on FGF23. The gene discussed is FGF23; the disease is hypercalcemia disease.