Question

Besides corticotropin-releasing hormone(CRH) which other hormones also stimulate the release of adrenocorticotropic hormone(ACTH)?
(a) Glucagon
(b) Insulin
(c) Aldosterone
(d) Epinephrine

Answer 1

Hint: The other hormone, apart from CRH, that stimulates the release of ACTH is secreted by a gland that exists as paired structures over the top of the kidneys. The hormone is usually released in stressful conditions like fear or accident etc.

Complete step by step answer:
Adrenocorticotropic hormones (ACTH) or corticotropin is a polypeptide hormone synthesized in the anterior lobe of the pituitary gland and released in response to the corticotropin- releasing hormone from the hypothalamus.ACTH stimulates the adrenal gland to release epinephrine. When the levels of ACTH in the blood decreases, through the feedback mechanism, epinephrine will stimulate the hypothalamus to release CRH which will further induce the release of ACTH from the anterior pituitary.
- Glucagon is a peptide hormone released by the alpha or A- cells of the pancreas. It helps to increase the level of glucose in the blood. For this, it inhibits or reduces the occurrence of any such pathway that involves the catabolism of glucose like glycolysis or glycogenesis which uses glucose to produce glycogen.
- Insulin is a polypeptide hormone with two chains of amino acids linked by disulfide bridges. It acts antagonistically to glucagon and thus promotes the removal of the glucose in the blood by stimulating anabolic pathways like glycogen synthesis or gluconeogenesis.
- Aldosterone is a mineralocorticoid released from the adrenal cortex. Its secretion is under the control of angiotensin II. It acts on the tubules of the nephron to promote the absorption of sodium, which is followed by the reabsorption of water and an increased blood volume.
So, the correct answer is ‘(d) Epinephrine.’:

Note:
- The pituitary gland is connected to the hypothalamus by a stalk- like structure known as the infundibulum.
- It is divided into two regions- an anterior portion of adenohypophysis and a posterior portion known as neurohypophysis.
- The secretion of the adenohypophysis is under the control of stimulating or inhibiting hormones by the hypothalamus.