[Does hyperparathyroidism with normal blood calcium exist?].
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Adolescent↗
Biomedical subjects
O Florescu
Publications and source records attributed to O Florescu.
Calcitonin secretion in thyroid insufficiency.
The level of circulating calcitonin was followed up in 30 patients with severe hypothyroidism, diagnosed clinically and by laboratory examinations. Four of the patients under study had goiter. The complex investigation of phosphorus-calcium metabolism, including radioimmunoassay of calcitonin was made under basal conditions and after calcium loading. The results revealed low basal urinary calcium excretion and an increased skeletal uptake of calcium after loading. Calcitonin secretion persisted in 8 of the patients under basal conditions and it increased after calcium loading in another 14 of them, accounting for the increased "skeletal avidity" for calcium. The persistence of calcitonin secretion supports an earlier clinical observation concerning the relative integrity of the skeleton in patients with hypothyroidism. In the hypothyroid patients with goiter the results do not differ from those obtained in the remaining patients.
Adult↗
Calcitonin secretion in hyperthyroidism.
The level of circulatory calcitonin was determined by the RIA method in 45 hyperthyroid patients in evolution, before and after calcium stimulation or after pentagastrin injection. The basal calcitonin secretion was increased in only 7 of the 45 patients studied, exceeding 500 pg/ml. After a slow calcium loading the mean of calcitonin increased, but with variable individual values. The rapid calcium loading was not followed by significant increases after 30 minutes. After pentagastrin a secretory peak of over 1,800 pg/ml was obtained in 4/5 cases. Results point out the state of the calcitonin-secreting system in hyperthyroidism and its possible role in the skeleton protection in these patients.
Adolescent↗
Skeletal calcium retention in hyperthyroidism and in vitro calcitonin inactivation.
Studies on patients with severe hyperthyroidism revealed an increased skeletal avidity for calcium, expressed in terms of net retention, after a three-hour i.v. load of 10mg Ca/kg body weight. For the same hyperthyroid subjects the calcitonin inactivating potency of the sera was tested in vitro. The results were expressed as restant hypocalcemic potency of the calcitonin after incubation with the serum fractions. In hyperthyroid subjects two fractions in dilutions of 1:10 reduced the hypocalcemic activity of calcitonin by 75%. In normals this activity appeared only in one fraction. All these results suggest a prompt calcitonin release during calcium infusion which is however less efficient, probably because of the increased amount of calcitonin inactivating factor present in sera. The serum inactivating factor generally contributes to the short-time activity of calcitonin both in normals and in some clinical states with bone calcium imbalance.
Bone and Bones↗