Question

A variety of plants are used as folk medicine in the treatment of hypertension.
Laboratory analyses show that a purified extract from one of these plants decreases
production of aldosterone in an animal model.
Complete the sentences below to explain how this anti-hypertensive plant extract might
work. In each case indicate the enzyme, hormone or receptor targeted and explain how the
action of the extract on this target would result in reduced aldosterone production.
A. The purified extract inhibits…
(60-word limit)
B. The purified extract blocks…
(60-word limit)

Answer 1

Aldosterone production is under the control of Angiotensin . Angiotensin is produced as angiotensinogen by liver cells. Angiotensinogen is converted in to angiotensin which stimulates the adrenal cortex leading to the release of aldosterone. Aldosterone will bring narrowing of blood vesels and increase the absorption of Na from kidney to increase the blood presure. BY inhibiting the release of renin and by blocking the conversion of angiotensinogen to angiotensin , blood pressure can be controlled.

A. The purified extract will inhibit the release of Renin from kidneys. Juxta glomerular apparatus releases Renin in to the blood under the conditions of low blood Na levels or low glomerular filtration. SO the production of renin from juxta glomerular apparatus is inhibitted in the presence of the plant extract.

B. Liver produces Angiotensinogen in to the blood. It is converted in to angiotensin by the hormone produced by kidney called renin. The angiotensin will ultimately stimulate the aldosterone release from adrenal gland. Adrenal gland has receptors on its surface for angotensins. Blockage of these receptors will also prevent adrenal gland releasing aldosterone. Which will not rise the blood pressure. Such substances are Angiotensin receptor blockers or ARBs.