Biomedical subjects

G Maruani

Publications and source records attributed to G Maruani.

7 recordsLinked to original sources

PubMed2001

[Calcium-sensing receptors: physiology and pathology].

The near constancy of extracellular calcium concentration is required for the numerous physiological functions of extra- and intracellular calcium. This implies that any change in extracellular calcium concentration must be detected in order to allow the appropriate correction by the homeostatic systems. The identification and cloning of a calcium-sensing receptor (CaR), which is expressed in the plasma membrane of parathyroid cells as well as many other cell types, has been a major advance in the understanding of the mechanisms involved in the control of extracellular calcium concentration. In addition, it demonstrated that extracellular calcium concentration itself is the first informative hormone-like messenger in this system. CaR belongs to the C subfamily of seven transmembrane-spanning G protein-coupled receptors. Several inherited disorders in extracellular calcium homeostasis are due to both activating or inactivating mutations in CaR gene, strengthening the essential role of CaR in the control of calcium metabolism.

Calcium↗

PubMed2000

[Primary hyperparathyroidism].

Primary hyperparathyroidism is the third most frequent endocrine disorder. The condition required for diagnosis is inappropriately elevated secretion of parathyroid hormone (PTH) with respect to calcemia. Most often, the disease is due to a parathyroid adenoma, i.e. a monoclonal benign parathyroid tumor, less often to a parathyroid hyperplasia. The main tumorogenic mechanisms currently proposed are a DNA rearrangement in the PTH locus (transposition of the PTH promoter upstream to Cyclin D1/PRAD 1 gene) and a mutation of the gene responsible for multiple endocrine neoplasia type I. The clinical presentation has strikingly evolved towards a milder, asymptomatic form, frequently diagnosed on systematic screenings. Though the mechanism of hypercalcemia is better understood, several hypothesis are still being considered about the regulation of tumoral PTH secretion: the role of the expression of calcium-receptor in parathyroid gland cells, vitamin D receptor and estrogen receptor polymorphisms, etc. Surgery is still advised for symptomatic forms of the disease, either because of a bone involvement, or because of an evolutive nephrolithiasis. In the near future, the new calcium-receptor agonists could be a relevant therapeutic approach.

Humans↗

PubMed1977