Interference with the action of angiotensinconverting enzyme (ACE) is an effective means at reducing elevations in blood pressure. The circulating concentration of which of the following hormones would be affected as a consequence of the use of ACE inhibitors?
A) ACTH
B) aldosterone
C) corticotrophin-releasing hormone, CRH
D) estradiol
E) gonadotropin-releasing hormone, GnRH

Question

Quizplus · Accepted Answer

ACE inhibitors reduce the production of angiotensin II, which in turn decreases the secretion of aldosterone from the adrenal glands. Angiotensin-converting enzyme (ACE) is responsible for the cleavage of 2 amino acids from angiotensin I, generating angiotensin II. Angiotensin II is a peptide hormone of the rennin-angiotensin system responsible for regulation of blood pressure. The intra-renal baroreceptor system is a key mechanism for regulating renin secretion. A drop in pressure results in the release of renin from the juxtaglomerular cells of the kidneys. Renin secretion is also regulated by the rate of Na⁺ and Cl⁻ transport across the macula densa. The higher the rate of transport of these ions, the lower is the rate of renin secretion. The only function for renin is to cleave a 10-amino-acid peptide from the N-terminal end of angiotensinogen yielding angiotensin I. ACE action then generates angiotensin II, one of the most potent naturally occurring vasoconstrictors. In addition to the vascular effects, other physiological responses to angiotensin II include induction of adrenal cortex synthesis and secretion of aldosterone. Release of aldosterone leads to further Na+ retention by the kidneys with the consequences being an additional pressive effect on the vasculature. Thus, the use of ACE inhibitors would not only reduce the production of angiotensin II but also aldosterone.

Interference with the Action of Angiotensinconverting Enzyme (ACE) Is an Effective