Why does testosterone, a lipid-soluble signaling molecule that crosses the membranes of all cells, affect only target cells?
A) Only target cells retain the appropriate genes regulated by testosterone.
B) Intracellular receptors for testosterone are present only in target cells.
C) Only target cells possess the cytosolic enzymes that transduce the signal from testosterone to adenylyl cyclase.
D) Only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.

Question

Quizplus · Accepted Answer

Testosterone affects only target cells because intracellular receptors for testosterone are present only in target cells. These receptors allow testosterone to bind and initiate a series of biochemical reactions that ultimately lead to changes in gene expression and cellular function. Non-target cells do not have these receptors, so they are not able to respond to testosterone in the same way.

Why Does Testosterone, a Lipid-Soluble Signaling Molecule That Crosses the Membranes