Genetic deletion of the kidney sodium/proton exchanger-3 (NHE3) does not alter calcium and phosphate balance due to compensatory responses

The sodium/proton exchanger-3 (NHE3) plays a major role in acid–base and extracellular volume regulation and is also implicated in calcium homeostasis. As calcium and phosphate balances are closely linked, we hypothesized that there was a functional link between kidney NHE3 activity, calcium, and phosphate balance. Therefore, we examined calcium and phosphate homeostasis in kidney tubule–specific NHE3 knockout mice (NHE3loxloxPax8 mice). Compared to controls, these knockout mice were normocalcemic with no significant difference in urinary calcium excretion or parathyroid hormone levels.