I am super confused by the role of vitamin D. Does it cause bone RESORPTION or bone mineralisation. different sources say different things. thanks
ps. i am aware that it increases calcium absorption in the gut
It causes both. Vitamin D is essential for activity (and according to some texts, for the production) of osteocalcin and ALP, which promote bone mineralisation. When the levels of Ca are low in plasma, PTH production is stimulated, and secondary to this stimulation, vit D can cause bone resorption. SO the normal role would be bone mineralisation, but when associated with low plasma Ca, it can lead to bone resorption. There are other references which say that Bone resorption is caused by PTH, and the only role of vitamin D in case of low plasma Ca is to increase Ca absorption from GIT. See this:
It causes both. Vitamin D is essential for activity (and according to some texts, for the production) of osteocalcin and ALP, which promote bone mineralisation. When the levels of Ca are low in plasma, PTH production is stimulated, and secondary to this stimulation, vit D can cause bone resorption. SO the normal role would be bone mineralisation, but when associated with low plasma Ca, it can lead to bone resorption. There are other references which say that Bone resorption is caused by PTH, and the only role of vitamin D in case of low plasma Ca is to increase Ca absorption from GIT. See this: