Substance a Is Secreted by the Liver, Travels Through the Circulatory

Multiple Choice

Substance A is secreted by the liver, travels through the circulatory system bound to a carrier protein, and causes a change in gene expression in its target cell. Substance A is therefore a ligand for ____.

A) a receptor tyrosine kinase
B) a G-protein-coupled receptor
C) a steroid hormone receptor
D) a ligand-gated ion channel
E) guanylyl cyclase