Final answer:
A) the normal rat and the hypophysectomized rat. Goiter is an enlargement of the thyroid gland that can occur due to iodine deficiency or hypothyroidism. When the body is deficient in iodine, the thyroid gland cannot produce enough T3 and T4 hormones, leading to a compensatory increase in the production of TSH from the anterior pituitary gland. This increased TSH stimulates the thyroid gland to grow in size, resulting in goiter.
Step-by-step explanation:
Goiter is an enlargement of the thyroid gland that can occur due to iodine deficiency or hypothyroidism. When the body is deficient in iodine, the thyroid gland cannot produce enough T3 and T4 hormones, leading to a compensatory increase in the production of TSH from the anterior pituitary gland. This increased TSH stimulates the thyroid gland to grow in size, resulting in goiter.
Therefore, the injection of TSH would result in goiter in the normal rat and the hypophysectomized rat, as both have functional thyroid glands that can respond to increased TSH levels. When the body is deficient in iodine, the thyroid gland cannot produce enough T3 and T4 hormones, leading to a compensatory increase in the production of TSH from the anterior pituitary gland. When the body is deficient in iodine, the thyroid gland cannot produce enough T3 and T4 hormones, leading to a compensatory increase in the production of TSH from the anterior pituitary gland. In the hypophysectomized rat (a rat that has had its pituitary gland removed), the lack of TSH secretion from the pituitary gland can also lead to a lack of stimulation for the thyroid gland. However, when TSH is injected, it can stimulate the thyroid gland and cause goiter in the absence of endogenous pituitary TSH.