In an experiment to track the movement of growth factor molecules from secretion to the point of receptor binding in a particular species of mammal, a student found a 20-fold reduction in mm traveled when in the presence of an adrenal hormone. This is in part attributable to which of the following?
A) The growth factor is a paracrine signal.
B) The growth factor depends on osmosis.
C) The mammal only carries growth factor through the lymph.
D) The growth factor is an exocrine signal.
E) The growth factor is an endocrine signal.

Question

Quizplus · Accepted Answer

Paracrine signals act locally near the site of secretion, so the presence of an adrenal hormone likely affects the local environment, reducing the distance the growth factor travels.

In an Experiment to Track the Movement of Growth Factor