Nuclear fuel cycle. The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages.
Hormone responsiveness does appear if the osteoclasts are cultured in conditioned medium from osteoblasts that first have been exposed to PTH, suggesting an important role for osteoblasts in PTH-dependent bone resorption [citing references as early as 1986].
They produce parathyroid hormone (PTH). While the parathyroid glands control the levels of calcium and phosphorus and Vitamin D in the body, the main trigger for the release or production of PTH is the level of calcium in the blood. PTH helps regulate the amount of calcium in the body.