08-21-2007, 08:22 PM
sorry didnt see the second ya osteoclast
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physio q - drkap
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08-21-2007, 08:23 PM
bone collagen and other one i think is osteoblast.
08-21-2007, 08:23 PM
OK SOFT CAT HERE IS THE EXPLANATION...
There are at least three different PTH receptors. One also binds parathyroid hormone-related protein (PTHrP; see below) and is known as the hPTH/PTHrP receptor. A second receptor, PTH2 (hPTH2-R), does not bind PTHrP and is found in the brain, placenta, and pancreas. In addition, there is evidence for a third receptor, CPTH, which reacts with the carboxyl terminal rather than the amino terminal of PTH. The first two are serpentine receptors coupled to Gs, and via this heterotrimeric G protein they activate adenylyl cyclase, increasing intracellular cAMP. The hPTH/PTHrP receptor also activates PLC via Gq, increasing intracellular Ca2+ and activating protein kinase C .
08-21-2007, 08:32 PM
HERE WE GO..
In osteopetrosis, a rare and often severe disease, the osteoclasts are defective and are unable to resorb bone in their usual fashion so the osteoblasts operate unopposed. The result is a steady increase in bone density, neurologic defects due to narrowing and distortion of foramina through which nerves normally pass, and hematologic abnormalities due to crowding out of the marrow cavities. Mice lacking the protein encoded by the immediate-early gene c-fos develop osteopetrosis, and osteopetrosis also occurs in mice lacking the PU.1 transcription factor. This suggests that all these factors are involved in normal osteoclast development and function. |
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