The research protocol must give a clear indication of what follow up will be provided to the research participants and for how long. This may include a follow u, especially for adverse events, even after data collection for the research study is completed.
The two most important hormones for maintaining calcium levels in the body are parathyroid hormone (PTH) and 1,25(OH)2D (the active form of vitamin D).The major regulator is PTH, which is part of a negative feedback loop to maintain [Ca ++ ] ECF (see Humoral regulation).he two most important hormones for maintaining calcium levels in the body are parathyroid hormone (PTH) and 1,25(OH)2D (the active form of vitamin D).
1 The parathyroid hormone (PTH), secreted by the parathyroid glands, is responsible for regulating blood calcium levels; it is released whenever blood calcium levels are low.  PTH increases blood calcium levels by stimulating osteoclasts, which break down bone to release calcium into the blood stream.