Question

Which of the following results from the action of parathyroid hormone (PTH) on the renal tubule?

• A. Stimulation of calcium ions reabsorption in the distal tubule
• B. Stimulation of phosphate reabsorption in the proximal tubule
• C. Interaction with receptors on the luminal membrane of the proximal tubular cells
• D. Decreased urinary excretion of cyclic adenosine monophosphate (CAMP)

Answer 1

The correct option is A Stimulation of calcium ions reabsorption in the distal tubule

The function of parathyroid hormone is to increases the Ca${}^2$${}^{+}$ levels in the blood.
The following are the ways in which they function:

1) It stimulates calcium ions reabsorption in the renal distal tubule. Reabsorption is the process by which the nephron removes water and solutes from the tubular fluid (pre-urine) and returns them to the circulating blood.
2) It increases calcium ions by absorption from the digested food.
3) It acts on bones and stimulates the process of bone reabsorption (dissolution).

Along with thyrocalcitonin (which lowers the levels of calcium in the blood by promoting formation of bone) it plays a significant role in calcium balance in the body.