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].
PTH essentially acts to increase the concentration of calcium in the blood by acting upon the parathyroid hormone 1 receptor, which is present at high levels in bone and kidney, and the parathyroid hormone 2 receptor, which is present at high levels in the central nervous system, pancreas, testis, and placenta.