Parathyroid Hormone (1-34), bovine is a potent parathyroid hormone (PTH) receptor agonist. Parathyroid Hormone (1-34), bovine increases calcium and inorganic phosphate levels in vivo. Parathyroid Hormone (1-34), bovine can be used for th reseach of osteoporosis.In Vitro: Parathyroid Hormone (1-34), bovine (0.1-100 ng/mL; 2-20 days) are added to the medium, it inhibits osteoblast proliferation in a dose-dependent manner. In another group, bPTH are added to the culture medium from day 1 to day 10, but not from days 11 to 20, a rebound of proliferation is observed in the PTH Day 1–10 group after bPTH withdrawal.Parathyroid Hormone (1-34), bovine (0.1-100 ng/mL; 2-20 days) induces diverse effects on the calcium and phosphorus content of culture medium. The calcium and phosphorus content of culture medium in the PTH-C 100 ng/mL group are higher than in teh control group.In Vivo: Parathyroid Hormone (1-34)(subcutaneous?injection; 80 μg/kg; 5 days) increases serum osteocalcin concentrations without changing serum inorganic phosphate or calcium concentrations in either group of old animals.?Serum 1,25-dihydroxyvitamin D concentrations are significantly higher in the PTH-treated senile female rats than the sex-matchedvehicle-treated controls.