Thyroid is latest success in regenerative medicine.
Hormone-producing gland can be created from embryonic stem cells.

Remarkably, the stem-cell-derived thyroid cells spontaneously grouped into follicles similar to those in an intact thyroid gland. And Costagliola and her colleagues found that the follicles were able to trap iodide and synthesize thyroid hormones. “When started the project, our hope was to get some cells that could be used to study thyroid physiology,” says Costagliola. “We never expected to get thyroid follicles.” (...)

The next step was to see how these follicles would function in live mice, and to assess their potential to correct hypothyroidism. This condition was induced in mice with an injection of radioactive iodine that accumulated in their thyroid glands, causing the tissue to wither away. Four weeks later, once hypothyroidism had been established, the mice received a graft of stem-cell-derived thyroid follicles. Out of nine mice treated in this way, eight showed complete rescue — their thyroid hormones returned to normal levels.

Source / Read more: Nature.com or Generation of functional thyroid from embryonic stem cells (PDF Full)