Acute antiosteoclastic effect of salmon calcitonin in osteoporotic women

Summary

Twenty-one women with primary osteoporosis received an intramuscular injection of 100 IU of salmon calcitonin at 8am. Blood samples were collected up to 5 h postcalcitonin and urine was collected for 24 h in three periods of 8 h each. A significant fall of the total hydroxyproline excretion (THP) was observed in every period but the maximum effect took place 8–16 h postcalcitonin. The effect was more pronounced in those patients with a greater basal excretion of THP and in those with a more significant diminution of their bone mass. A significant diminution of the urinary excretion of calcium was found 8–24 h postcalcitonin, while phosphate excretion increased throughout the three 8 h periods. The effect of calcitonin in osteoporotic women was compared with the results obtained in 9 patients with Paget's disease. In absolute values the fall of THP excretion was significantly greater in the pagetic patients but the percentage diminution was not significantly different in osteoporotic women and in pagetic patients. Salmon calcitonin induced a significant acute diminution of bone turnover in patients with osteoporosis, as defined by decreases in total urinary hydroxyproline. The calcitonin-induced hypocalcemia does not seem to be an accurate index of the hormone action in osteoporosis.