AP BIOLOGY

Detailed explanation-1: -Testosterone acts on cells through intracellular transcription-regulating androgen receptors (ARs).

Detailed explanation-2: -The actions of androgens such as testosterone and dihydrotestosterone are mediated via the androgen receptor (AR), a ligand-dependent nuclear transcription factor and member of the steroid hormone nuclear receptor family.

Detailed explanation-3: -Receptors for steroid hormones are usually found within the protoplasm and are referred to as intracellular or nuclear receptors, such as testosterone. Upon hormone binding, the receptor can initiate multiple signaling pathways, which ultimately leads to changes in the behavior of the target cells.

Detailed explanation-4: -Testosterone binds to a receptor protein in the cytoplasm, activating it. The hormone-receptor complex enters the nucleus and binds to specific genes. The bound protein acts as a transcription factor, stimulating the transcription of the gene into mRNA. The mRNA is translated into a specific protein.

Detailed explanation-5: -Testosterone appears to be the primary androgen receptor-activating hormone in the Wolffian duct, whereas dihydrotestosterone is the main androgenic hormone in the urogenital sinus, urogenital tubercle, and hair follicles.