You are an experimental endocrinologist studying the effects of a peptide analog on the functions of the kidney. When you administer the analog to laboratory mice you are able to measure a significant increase in urinary excretion of sodium. Which of the following known peptides exerts effects most similar to your peptide analog?
A) atrial natriuretic peptide
B) calcitonin
C) irisin
D) oxytocin
E) renin

Question

Quizplus · Accepted Answer

Atrial natriuretic peptide (ANP) is known to increase the excretion of sodium in the urine, a process known as natriuresis, which aligns with the effects observed with the peptide analog in the study.  Natriuresis refers to enhanced urinary excretion of sodium. Atrial natriuretic peptide (ANP) was the first cardiac natriuretic hormone identified. This hormone is secreted by cardiac muscle when sodium chloride intake is increased and when the volume of the extracellular fluid expands. Although the precise mode of action of ANP to increase sodium excretion has not been characterized, it is known that ANP induces relaxation of the mesangial cells of the glomeruli and thus may increase the surface area of these cells so that filtration is increased. Alternatively, ANP might act on tubule cells to increase sodium excretion.

You Are an Experimental Endocrinologist Studying the Effects of a Peptide