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].
Thyroid-releasing hormone (TRH) from the hypothalamus stimulates TSH from the pituitary, which stimulates thyroid hormone release. As blood concentrations of thyroid hormones increase, they inhibit both TSH and TRH, leading to shutdown of thyroid epithelial cells.