Calcium: outside/inside homeostasis and signalling

The mechanisms of calcium homeostasis and signalling in the lens.

Excessive Ca(2+) can be detrimental to cells and raised levels of Ca(2+) in human lenses with cortical cataract have been found to play a major role in the opacification process. Ca(2+) homeostasis is therefore, recognised as having fundamental importance in lens pathophysiology. Furthermore, Ca(2+) plays a central role as a second messenger in cell signalling and mechanisms have evolved which ...

ANTICONVULSANT THERAPY-INDUCED ALTERATIONS IN CALCIUM HOMEOSTASIS

35 epileptic patients, aged 10 to 58 years (mean 23), who were taking anticonvulsant drugs were studied. The patients exhibited a 34% reduction in serum calcium levels, a 41 % increase in serum alkaline phosphatase activity and a slight but insignificant decrease in serum phosphate, compared to untreated controls. These changes appear to be related to the anticonvulsant drug taken, in the ...

Kidney and Calcium Homeostasis

Plasma calcium concentration is maintained within a narrow range (8.5-10.5 mg/dL) by the coordinated action of parathyroid hormone (PTH), 1,25(OH)2D3, calcitonin, and ionized calcium (iCa(2+)) itself. The kidney plays a key role in this process by the fine regulation of calcium excretion. More than 95% of filtered calcium is reabsorbed along the renal tubules. In the proximal tubules, 60% of fi...

Calcium and Magnesium Homeostasis

Calcium signalling

Cellular signalling mechanisms are designed to transmit information from the cell surface membrane to specific targets within the cell. Often, the information is transmitted by means of intracellular messengers, of which the calcium ion, Ca2+, is one of the most important. Indeed, Ca2+ operates throughout the life history of a typical cell: it triggers new life at fertilisation, it controls man...