Question

1. Which of these hormones is regulated by a very similar feedback mechanism to that of the regulation of cortisol?

   		glycogen
   		Insulin.
   		T3 and T4.
   		Glucagon

Answer 1

Cortisol is a steroid hormone secreted by cortex of adrenal gland. It secretion is regulated by feedback loop as follows

When the cortisol level less in the blood, Corticotropin-releasing hormone (CRH) from the hypothalamus enhances the release of Adrenocorticotropic hormone (ACTH) from the anterior pituitary. ACTH stimulates the cortex of adrenal gland to release cortisol and cortisol level increase in the blood. When cortisol more in the blood, it inhibits anterior pituitary and hypothalamus through feedback mechanism and decrease the release of CRH from hypothalamus and ACTH from anterior pituitary.

Similar mechanism take place in case of thyroid hormones (T3 and T4)

When thyroid hormones level less in the blood, Thyrotropin-releasing hormone (TRH), from the hypothlamus enhances the release of Thyroid-stimulating hormone (TSH) from the anterior pituitary. TSH stimulates the follicular cells of thyroid gland to release thyroid hormones (T3 and T4) and thyroid hormones level increase in the blood. When thyroid hormones more in the blood, it inhibits anterior pituitary and hypothalamus through feedback mechanism and decrease the release of TRH from hypothalamus and TSH from anterior pituitary. Ultimately decreases the secretion of thyroid hormones and decrease its level in the blood

Answer is T3 and T4