Overview of the effects of PTH

2021-06-06 01:07 PM

PTH stimulates bone resorption, the release of calcium into the extracellular fluid, increases calcium reabsorption and decreases tubular phosphate reabsorption, leading to decreased calcium excretion and increased phosphate excretion.

Figure summarizes the main effects of increased PTH secretion in response to decreased calcium concentration in the extracellular fluid: (1) PTH stimulates bone resorption, releasing calcium into the extracellular fluid; (2) PTH increases calcium reabsorption and decreases tubular phosphate reabsorption, leading to decreased calcium excretion and increased phosphate excretion; and (3) PTH is required for the conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, which enhances intestinal calcium absorption. The above effects exert a great power to regulate the concentration of extracellular fluid calcium.

Figure. Overview of the effects of parathyroid hormone (PTH) on the bones, kidneys, and intestines in response to any reduction in foreign calcium ion concentrations. CaSR, calcium-sensing receptor.