A friend of yours is diagnosed with hypothyroidism and shows you the results of her most recent blood tests. The level of thyroxine is below normal, but the levels of thyroid-stimulating hormone (TSH) and thyroid-releasing hormone (TRH) are above normal. Whihc of the following is the best explanation for these results?
The TSH receptors in the thyroid are unable to respond to the TSH produced by the pituitary.