Physiological studies in heterozygous calcium sensing receptor (CaSR) gene-ablated mice confirm that the CaSR regulates calcitonin release in vivo
| العنوان: | Physiological studies in heterozygous calcium sensing receptor (CaSR) gene-ablated mice confirm that the CaSR regulates calcitonin release in vivo |
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| المؤلفون: | Fudge, Neva J, Kovacs, Christopher S |
| المصدر: | BMC Physiology, Vol 4, Iss 1, p 5 (2004) BMC Physiology |
| بيانات النشر: | BMC, 2004. |
| سنة النشر: | 2004 |
| مصطلحات موضوعية: | Mice, Knockout, Dose-Response Relationship, Drug, Genotype, lcsh:QP1-981, familial hypocalciuric hypocalcemia, Hyperparathyroidism, gene knock-out, Animal models/rodent, lcsh:Physiology, Mice, calcitonin, Hypercalcemia, Animals, Calcium, calcium receptor, Receptors, Calcium-Sensing, hormones, hormone substitutes, and hormone antagonists, Research Article |
| الوصف: | Background The calcium sensing receptor (CaSR) regulates serum calcium by suppressing secretion of parathyroid hormone; it also regulates renal tubular calcium excretion. Inactivating mutations of CaSR raise serum calcium and reduce urine calcium excretion. Thyroid C-cells (which make calcitonin) express CaSR and may, therefore, be regulated by it. Since calcium stimulates release of calcitonin, the higher blood calcium caused by inactivation of CaSR should increase serum calcitonin, unless CaSR mutations alter the responsiveness of calcitonin to calcium. To demonstrate regulatory effects of CaSR on calcitonin release, we studied calcitonin responsiveness to calcium in normal and CaSR heterozygous-ablated (Casr+/-) mice. Casr+/- mice have hypercalcemia and hypocalciuria, and live normal life spans. Each mouse received either 500 μl of normal saline or one of two doses of elemental calcium (500 μmol/kg or 5 mmol/kg) by intraperitoneal injection. Ionized calcium was measured at baseline and 10 minutes, and serum calcitonin was measured on the 10 minute sample. Results At baseline, Casr+/- mice had a higher blood calcium, and in response to the two doses of elemental calcium, had greater increments and peak levels of ionized calcium than their wild type littermates. Despite significantly higher ionized calcium levels, the calcitonin levels of Casr+/- mice were consistently lower than wild type at any ionized calcium level, indicating that the dose-response curve of calcitonin to increases in ionized calcium had been significantly blunted or shifted to the right in Casr+/- mice. Conclusions These results confirm that the CaSR is a physiological regulator of calcitonin; therefore, in response to increases in ionized calcium, the CaSR inhibits parathyroid hormone secretion and stimulates calcitonin secretion. |
| اللغة: | English |
| تدمد: | 1472-6793 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=pmid_dedup__::67dcac2d77c4dbf8b5499a4bc4c0f921Test http://www.biomedcentral.com/1472-6793/4/5Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.pmid.dedup....67dcac2d77c4dbf8b5499a4bc4c0f921 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14726793 |
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