Low levels of which hormone can lead to increased calcium levels in the blood?

The correct response is related to the role of calcitonin in regulating calcium levels in the blood. Calcitonin is a hormone produced by the thyroid gland that helps to lower blood calcium levels by inhibiting bone resorption (the process through which bones release calcium into the bloodstream) and promoting the excretion of calcium through the kidneys.

When there are low levels of calcitonin, the inhibitory effect on bone resorption is diminished, allowing for increased release of calcium from bones into the bloodstream. This can lead to higher levels of calcium in the blood.

Understanding the functions of hormones like calcitonin is crucial for managing conditions related to calcium metabolism and bone health. In contrast, while parathyroid hormone (PTH) typically raises blood calcium levels when secreted, low levels of it do not contribute to increased blood calcium in the same manner as low calcitonin. Estrogen and thyroid hormones, while influential to various metabolic processes, do not have the direct regulatory effect on calcium levels like calcitonin does.