These authors find that measurement of serum 25-hydroxyvitamin D is assay dependent. They examined three different methods to determine serum 25-hydroxyvitamin D, high-pressure liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS), a radioimmunoassay (RIA) and a chemiluminescent immunoassay (CLIA) using identical samples. HPLC-APCI-MS produced the highest values, RIA was intermediate and CLIA produced the lowest results.

The authors find that mice with a targeted deletion of the insulin receptor in osteoblasts have low circulating undercarboxylated osteocalcin, decreased bone formation rates and decreased bone mass. With age these mice develop obesity, insulin resistance and hyperglycemia, which are corrected by infusion of undercarboxylated osteocalcin.

The authors demonstrate that neighbor of Brca1 (Nbr1) has a role in osteoblast function through its ability to regulate p38 MAPK.

The authors examined the role of activating transcription factor 4 (ATF4) in osteoclasts. They targeted expression of ATF4 to the OCL lineage using the Trap promoter or through deletion of Atf4 in mice and found it regulated NFAT2 and osteoclastogenesis.

The authors examined the risk factors associated with the development of the acute phase response to zoledronic acid treatment. They found that young age and the use of non-steroidal anti-inflammatory drugs increased the likelihood of developing this condition.