USMLE Forum - Largest USMLE Community

You are working in a research laboratory studying cardiovascular function. The studies in that laboratory use a "knockout" mouse in which the gene for atrial natriuretic peptide (ANP) is deleted. Which of the following would you most likely find elevated?

a. ANP levels in the bloodstream
b. Excretion of urine
c. Excretion of sodium
d. Peripheral vasoconstriction
e. Capillary permeability

DD..

DD

d. Peripheral vasoconstriction

D. is correct

anyone can tell me y? i dont get it

ANP is released from the atria in response to atrial stretch and/or endothelin-1 stimulation. ANP usually causes relaxation of vascular smooth muscle and counteracts the effect of aldosterone. Therefore, in its absence, sodium and water retention will increase, as well as vasoconstriction, resulting in elevated blood pressure.