Final answer:
The main target of calcitonin is the skeletal system, and it functions to lower blood calcium levels by affecting bone cells. Despite the lack of a recognized disease caused by calcitonin deficiency, pharmacological doses are used in the treatment of osteoporosis to slow bone loss.
Step-by-step explanation:
Main Target of Calcitonin
The main target of calcitonin is the skeletal system, specifically the cells involved in bone remodeling, such as osteoclasts and osteoblasts. Calcitonin is a hormone produced by the parafollicular cells of the thyroid gland. Its primary action is to lower blood calcium levels. It achieves this by inhibiting osteoclast activity, which decreases bone resorption, and by stimulating osteoblasts, which promotes bone formation. Additionally, calcitonin enhances the excretion of calcium through the kidneys.
Calcitonin Deficiency Disease
Regarding disease due to calcitonin deficiency, it is important to note that the role of calcitonin in adults is not well-understood and it's typically not considered critical for calcium homeostasis. Thus, a specific disease caused by calcitonin deficiency is not recognized. However, pharmacological doses of calcitonin are used in the treatment of conditions such as osteoporosis, where the goal is to reduce the activity of osteoclasts and slow down bone loss.