Epinephrine is a protein hormone found in many animals. epinephrine stimulates a signaling pathway that results in the breakdown of glycogen to glucose in the liver cells. which of the following describes the initial steps in the process whereby epinephrine stimulates glycogen breakdown? a) epinephrine binds to a cell-surface receptor; the activated receptor stimulates production of the second messenger, camp. b) epinephrine binds to a cell-surface receptor; the activated receptor catalyzes the conversion of glycogen to glucose. c) epinephrine diffuses through the plasma membrane; the hormone dimerizes in the cytosol. d) epinephrine is taken into the cell by endocytosis; glycogen is converted to glucose in the endocytotic vesicle.