Figure 5.
PTH suppresses phosphate-induced mitochondrial Erk1/2 phosphorylation and mitochondrial Bad. A, Hypertrophic chondrocytes were pretreated for 30 minutes with (+) or without (−) 10−6 M, 10−7 M, and 10−8 M PTH prior to a 30-minute incubation with 7 mM sodium sulfate (−) or sodium phosphate (+). Western analyses were performed to evaluate phospho-Erk1/2 (pERK) and total Erk1/2 (TERK). B, Subcellular fractionation of hypertrophic chondrocytes pretreated with (+) or without (−) 10−7 M PTH prior to incubation with 7 mM sodium sulfate (−) or phosphate (+) for 1 or 4 hours. Western analyses were performed on cytosolic (C) and mitochondrial (M) fractions. VDAC (mitochondrial control) and HSP90 (cytosolic control). Data are representative of those obtained from three independent chondrocyte preparations. The line in B (1 hour data) indicates that the two panels were not contiguous on the same gel.