Animal experiment:

To identify apoptosis in parathyroid glands from 5/6 nephrectomized or sham rats treated with vehicle [phosphate-buffered saline (PBS)] or Cinacalcet (10 mg/kg), nuclear DNA fragmentation is measured in situ using the Apoptag System. Briefly, parathyroid gland sections from animals treated with vehicle or cinacalcet HCl are digested with 20 μg/mL proteinase K in 0.1 mol/L PBS at room temperature for 15 minutes and incubated with 3% hydrogen peroxide/methanol for 5 minutes to block endogenous peroxidase. Sections are incubated for 1 hour at 37℃ with terminal deoxynucleotidyl transferase (TdT) to label exposed 3′-OH DNA ends with digoxigenin-tagged nucleotides. Digoxigenin-labeled DNA is detected by the immunoperoxidase method. Sections are developed with 3,3′-diaminobenzidine (DAB), and the nuclei of apoptotic cells are stained brown. The specificity for apoptosis is verified by negative staining when distilled water is substituted for TdT.

Cinacalcet HCl (AMG 073), the second-generation calcimimetic, is a potent agonist of calcium-sensing receptor (CaR) with an EC50 value of 2.8 μm [1].

Cinacalcet HCl showed to be safe for the secondary hyperparathyroidism treatment. Besides, cinacalcet HCl has been proved to reduce parathyroid hormone (PTH) levels significantly while reducing the calcium x phosphorus product and serum phosphorus levels at the same time [1].

Administered orally with cinacalcet in Rice H-500 tumor bearing mice has shown a significant reduction of blood ionized calcium, serum total calcium concentrations and serum PTHrP levels [2].

References:
[1] Urena P1, Frazao JM. Calcimimetic agents: review and perspectives. Kidney Int Suppl. 2003 Jun;(85):S91-6.
[2] Colloton M1, Shatzen E, Wiemann B, Starnes C, Scully S, Henley C, Martin D.Cinacalcet attenuates hypercalcemia observed in mice bearing either Rice H-500 Leydig cell or C26-DCT colon tumors. Eur J Pharmacol. 2013 Jul 15;712(1-3):8-15.