The human pituitary gland secretes thyroid-stimulating hormone (TSH).TSH stimulates the thyroid gland to release thyroxine, a hormone that regulates metabolism.TSH has no effect on heart cells.Based on your knowledge of membrane receptors, what can you say about how cells in the thyroid gland compare with heart cells?
A) Thyroid cells, but not heart cells, contain the gene encoding the protein that makes up the TSH receptor.
B) Both thyroid cells and heart cells make TSH receptors on their cell surfaces, but only thyroid cells respond to TSH signals.
C) Both thyroid cells and heart cells have the gene for the TSH receptor, but only thyroid cells express the gene.
D) Heart cells, but not thyroid cells, inhibit binding of TSH to TSH receptors on their cell surfaces.
E) Heart cells, but not thyroid cells, use their TSH receptors to bind to a signal other than TSH.

Question

Quizplus · Accepted Answer

Thyroid cells respond to TSH because they express the TSH receptor gene, allowing them to produce TSH receptors on their cell surfaces. Heart cells, despite having the gene, do not express it, and thus do not respond to TSH.

The Human Pituitary Gland Secretes Thyroid-Stimulating Hormone (TSH)