Traditionally,
arginine vasopressin modulation of
renal water,
sodium, and urea excretion has been considered somewhat in isolation from factors that control divalent mineral ion homeostasis. Similarly, previous considerations of divalent mineral ion metabolism have focused mainly on the role of
hormones, eg,
parathyroid hormone and various forms of vitamin D, as principal modifiers of
renal calcium handling. Recent data, however, have now suggested the existence of
novel linkages that
coordinate control of water and divalent mineral ion homeostasis. This article summarizes these data and highlights the fundamental roles of the
extracellular calcium polyvalent cation-sensing receptor (CaR) as an integrator of water and divalent mineral ion homeostasis on a
cellular,
organ-specific, and whole-body basis.
Organs where CaRs may integrate water and divalent mineral ion metabolism include
endocrine tissues that
express CaRs, the brain, various
nephron segments of the
kidney, bone, and the
gastrointestinal tract. These new data suggest that considerable
regulatory overlap exists between water and divalent mineral ion homeostasis.