Fig. 3.

Effects of PTH on the STC1 expression in OK-P cells and rat kidney. (A, B) OK-P cells were incubated with the control (final concentration of ethanol, 0.1%) and 100 nM PTH for 6 h or different periods of time. The mRNA levels of STC1 and STC2 in OK-P cells were determined by RT-PCR and real-time PCR analysis. (C, D) SD male rats were fed a low-phosphate diet for 3 days, low-phosphate diet contained 0.02% Pi and 0.6% Ca, and then 10 µg human PTH (1–34)/100 g body weight was injected into the jugular vein. After treatment for 0.5 h and 3 h, the mRNA expression levels of STC1 in kidney were quantified by real-time PCR. Results were normalized to the mRNA expression level of β-actin. Values are means ± SD (n = 3–5). *p<0.05, **p<0.001 compared with control. (D) The renal protein levels of STC1 and NaPi-2a were measured by western blot analysis. β-actin was used as an internal control.