Circulating levels of calciotropic hormones during treatment with nasal salmon calcitonin

Intranasal salcatonin (salmon calcitonin). A review of its pharmacological properties and role in the management of postmenopausal osteoporosis

Osteoporosis is a common problem among postmenopausal women and is associated with significant morbidity, mortality and costs primarily resulting from osteoporotic fractures. Salcatonin (salmon calcitonin) inhibits osteoclastic bone resorption and is approximately 40 to 50 times more potent than human calcitonin. In most randomised trials in which intranasal salcatonin (usually 50 to 200 IU/day plus oral calcium supplements) was administered for 1 to 5 years to postmenopausal women for prevention of osteoporosis, bone mineral density or content of the lumbar spine increased by approximately 1 to 3% from baseline. In contrast, postmenopausal women receiving only oral calcium supplements typically had reductions in bone mineral density or content of about 3 to 6%. The difference between treatment groups was statistically significant in essentially all studies. Although changes in bone mineral density or content were broadly similar in studies of postmenopausal women with established osteoporosis to those in postmenopausal women receiving therapy for prevention of the disease, studies in women with established osteoporosis did not usually demonstrate statistically significant differences between treatment groups. Also in postmenopausal women with established osteoporosis, intranasal salcatonin reduced pain and/or analgesic consumption in some trials and, in a limited number of studies of relatively short duration (i.e. < or = 2 years), the incidence of osteoporotic fractures. A large multicentre 5-year study with adequate statistical power to confirm the effect of intranasal salcatonin on reducing osteoporotic fracture rates in postmenopausal women is currently under way. The intranasal formulation of salcatonin offers a more convenient and better tolerated alternative to the parenteral formulation of the drug which is administered by regular subcutaneous or intramuscular injections. Adverse events associated with the intranasal formulation are generally mild and transient, usually involving local reactions such as nasal discomfort, rhinorrhoea or rhinitis. Thus, for postmenopausal women unable or unwilling to tolerate long term hormone replacement therapy, intranasal salcatonin is an attractive alternative for the management of osteoporosis.

Effect of nasal salmon calcitonin on bone remodeling and bone mass in postmenopausal osteoporosis

The effect of nasal salmon calcitonin (SCT) on bone has been investigated by densitometry, biochemical markers of bone turnover, and histomorphometry. 62 women (mean age 65 years) who had experienced Colles' fracture after menopause were randomized to receive either nasal salmon calcitonin (SCT) 200 IU or nasal placebo daily for 24 months. All received a daily supplement of 0.5 g calcium. There was a significant increase above baseline in the bone mineral density of the lumbar spine in the SCT group (2.5%; 95% confidence interval 0.9--4.2%) and in the placebo group (1.7%; 95% confidence interval 0.3--3.1%) after 24 months, but the difference between the groups was not significant (0.8%; 95% confidence interval -1.2-3.0%). Serum levels of osteocalcin decreased significantly below baseline in the SCT group, whereas they were unchanged in the placebo group. At months 12 and 24, serum levels of osteocalcin were significantly lower in the SCT group than in the placebo group (p < 0.03). Urinary levels of deoxypyridinoline/creatinine decreased significantly below baseline in the SCT group, whereas only a transient decrease was observed in the placebo group. The differences between the groups were, however, not significant. The erosion depth was significantly lower in the SCT group than in the placebo group after 12 months (median [interquartile range]; 46.9 mu m [10.4] vs. 50.5 mu m [10.7]; p = 0.03), whereas bone volume and activation frequency did not differ between the groups. This study indicates that nasal SCT in a dose of 200 IU daily induces only a minor inhibition of bone resorption and therefore produces only a minor increase in bone mass. Furthermore, it seems that nasal SCT in a dose of 200 IU does not interfere with the recruitment of new bone multicellular units, but preferably decreases ongoing osteoclastic bone resorption.

Acute effects of nasal salmon calcitonin on calcium and bone metabolism

Effects of a single dose of 200 IU of nasal salmon calcitonin (SCT) on calcium metabolism and biochemical markers of bone turnover were investigated in 12 healthy male volunteers in a randomized, placebo-controlled, cross-over design. The nasal spray was given in the morning, and subsequently blood and urine samples were collected for 26 hours. There was a significant decrease in serum ionized calcium with a nadir 4 hours after administration of nasal SCT accompanied by a significant increase in serum parathyroid hormone (P = 0.01) and serum calcitriol (P = 0.04). Nasal SCT did not reduce urinary hydroxyproline/creatinine. Urinary deoxypyridinoline/creatinine was lowered significantly 2 hours after administration of nasal SCT and throughout the first 24 hours, but remained unchanged for the last 2 hours. On a 24-hour basis, urinary deoxypyridinoline/creatinine decreased from 14.1 (3.5) nmol/mmol to 11.7 (3.2) nmol/mmol after nasal SCT (P = 0.04). Nasal SCT did not change the serum levels of alkaline phosphatase, osteocalcin, and the carboxyterminal propeptide of type 1 procollagen. The results indicate that nasal SCT given as a single dose provokes a modest decrease in bone resorption lasting several hours, but leaves bone formation unaffected.

Plasma levels of parathyroid hormone, vitamin D, calcitonin, and calcium in association with endurance exercise

Nine male marathon runners were investigated during habitual training (week 0), after 3 weeks of training break (week 3), and after 2 weeks (week 5) and 4 weeks (week 7) of retraining. Maximal oxygen uptake, body fat (BF), and plasma levels of 25(OH)D3, 1,25(OH)2D3, parathyroid hormone (PTH), calcitonin (CT), albumin, and albumin-corrected calcium were determined throughout weeks 0-7. The maximal oxygen uptake decreased after training break and increased during retraining (P = 0.002). BF did not change significantly. Plasma 1,25(OH)2D3 was elevated after training break and decreased after 2 and 4 weeks of retraining [week 0: 44.0 +/- 3.7 (SEM) pg x 1(-1); week 3: 52.4 +/- 6.0 pg x 1(-1); week 5: 42.0 +/- 2.8 pg x 1(-1); week 7: 36.9 +/- 2.3 pg x 1(-1); P = 0.03]. Plasma 25(OH)D3 did not change significantly. Plasma PTH increased throughout the training break and retraining (week 0: 1.36 +/- 0.25 pmol x 1(-1); week 3: 2.02 +/- 0.43 pmol x 1(-1); week 5: 2.23 +/- 0.60 pmol x 1(-1); week 7: 2.63 +/- 0.34 pmol x 1(-1); P = 0.03). Albumin-corrected calcium values were transiently decreased during retraining (week 3: 2.77 +/- 0.08 mM; week 5: 2.47 +/- 0.05 mM; week 7: 2.66 +/- 0.07 mM; P = 0.01). Plasma CT did not change during training break, but was transiently decreased during retraining (week 0: 9.97 +/- 0.39 pmol x 1(-1); week 3: 9.91 +/- 0.37 pmol x 1(-1); week 5: 8.19 +/- 0.50 pmol x 1(-1); week 7: 9.02 +/- 0.45 pmol x 1(-1); P = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)