mayblin, my hypothetical is that pth pulls calcium from various sources and into the bloodstream. Forteo induces more absorption from the intestine, draws back calcium from the kidneys and pulls calcium from the bone. My thought is that if the calcium supply is sufficiently available, the bone stores of calcium can remain untouched.
Conversation with a bone reseacher, though with some intricacies that I retained only the conclusion to, my suspicions were loosely confirmed.
If I can find those notes,
I worried that drawing calcium from bone might be an important step in anabolism. Doesn't it seem like taking calcium from the bone would stimulate osteoblasts? I'm told not.
Windyshores' answer is reassuring.
In that vein, if a person is having side effects, I'd want to experiment lowering calcium intake (dramatically if I were the patient) to see if I could eliminate the adverse effect.
I've read about lowering calcium intake or lowering D3 to decrease absorption. The body regulates circulating calcium even to the detriment of other organs in to protect the brain. So serum levels of calcium aren't reliable for determining parathyroid disease for example.
I think you have to experiment, but we don't get tested often enough to go by numbers.
I also think we are too-calcified. My thinking (in all areas) remains suspect.