Calcitonin und Osteoporose — Kritische Durchsicht der Literatur 1980–1989

Abstract

Due to increasing old age and a prolonged life expectancy osteoporoses mainly of the involutional type have become very common and are thus of prime socio-medical importance. Recently considerable attention has been given to calcitonin as an aetiologic, prophylactic and therapeutic agent in osteoporosis. Since the subject is very controversial, the present study aims at critically evaluating the pertinent literature from 1980-1989: 1. A decreased stimulability of the thyroid C-cells and thus a diminished calcitonin secretion capacity has been demonstrated in white postmenopausal women. However an overt calcitonin deficiency cannot be considered to be the only or a major cause of the osteoporotic bone loss. 2. An increased bone loss (occurring in phases?) may be stopped by calcitonin(s) given either parentally or by the intranasal route. This pharmacologic calcitonin effect does not differ from the well-known osteoclast inhibiting effect in Paget's disease and seems to be similar to estrogen bone effects in the menopause. 3. An increase of total body calcium (TbCa) of 1-4% and of the bone mineral content (BMC) has been reported occurring within 18-24 months of calcitonin administration in overt osteoporosis. However a reinforcement of the bone structure has not been shown, further crash fractures of vertebras occurring despite calcitonin administration for up to 2 years. Within this observation period the bone volume assessed histomorphometrically did not increase, unless calcitonin was combined with phosphates which were known to induce secondary hyperparathyroidism. 4. Repeatedly an analgesic efficacy has been ascribed to calcitonins, presumably due to a direct hormonal effect on calcitonin receptors in the brain. Since the pain in osteoporosis is extremely variable and often self-limiting due to fracture healing the "calcitonin analgesia" has probably been over-estimated.

Long-term excess of endogenous calcitonin in patients with medullary thyroid carcinoma does not affect bone mineral density

“…Our results are in contrast to several therapeutic studies showing positive effects of pharmacological doses of calcitonin given intermittently, either subcutaneously or intranasally, on bone mineral density (Gruber et al 1984;Ringe & Wenzel, 1987;Haas et al 1990). The percentage of postmeno¬ pausal women was not higher in the group of patients with elevated calcitonin levels.…”

Effects of Endogenous and Exogenous Calcitonin on Inflammation-Mediated Osteopenia in the Rat

“…IMO was prevented by treatment with 1,25-dihydroxyvitamin Dy [8], a substance known to be able to stimulate bone resorption. The present results are in contrast to pre vious studies, having shown positive effects of CT on bone mass, also in low turnover states of bone metabolism [ 13]. However, in that study.…”

“…This is in contrast to results showing diminished CT secretion in postmenopausal osteoporosis [13]. Inhibition of osteoblasts has been shown to occur in IMO already at day 3 after induction of IMO [3,4], and there is increased urinary calcium excretion [5].…”