A 48-year-old woman presents for evaluation after routine bl…
A 48-year-old woman presents for evaluation after routine bloodwork shows low calcium levels. In response to this decrease, her parathyroid glands are stimulated to release a hormone that increases calcium reabsorption in the kidneys, enhances calcium absorption in the small intestine (through activation of calcitriol), and promotes calcium release from bone. Once calcium levels return to normal, secretion of this hormone decreases through a negative feedback mechanism. Which hormone is primarily responsible for initiating this response?