Role of TGF-β in a mouse model of high turnover renal osteodystrophy.

Altered bone turnover is a key pathologic feature of chronic kidney disease-mineral and bone disorder (CKD-MBD). Expression of TGF-β1, a known regulator of bone turnover, is increased in bone biopsies from individuals with CKD. Similarly, TGF-β1 mRNA and downstream signaling is increased in bones from jck mice, a model of high-turnover renal osteodystrophy.

Intestinal npt2b plays a major role in phosphate absorption and homeostasis.

Intestinal phosphate absorption occurs through both a paracellular mechanism involving tight junctions and an active transcellular mechanism involving the type II sodium-dependent phosphate cotransporter NPT2b (SLC34a2). To define the contribution of NPT2b to total intestinal phosphate absorption, we generated an inducible conditional knockout mouse, Npt2b(-/-) (Npt2b(fl/fl):Cre(+/-)). Npt2b(-/-) animals had increased fecal phosphate excretion and hypophosphaturia, but serum phosphate remained unchanged.