FGF23 and secondary hyperparathyroidism: In contrast with the rodent models discussed above, in Fgf23-transgenic (Tg) mice, a model of FGF23 excess, secondary hyperparathyroidism, hypophosphatemia and hypotension, high FGF23 is accompanied by increased left ventricular mass, interventricular septum thickness and left ventricular posterior wall thickness [215].