Final answer:
Testosterone stimulates the production of enzymes and structural proteins in skeletal muscle fibers, leading to an increase in muscle size and strength.
Step-by-step explanation:
The steroid hormone testosterone stimulates the production of enzymes and structural proteins in skeletal muscle fibers through a series of steps:
- Binding to a receptor: Testosterone enters the muscle cells and binds to specific receptor proteins.
- Formation of a complex: The testosterone-receptor complex combines with DNA, forming a receptor protein-hormone complex.
- Enhancement of enzyme synthesis: This complex binds to specific sites on DNA and initiates or enhances the synthesis of messenger RNA (mRNA).
- Protein synthesis: The mRNA then directs the synthesis of proteins, including enzymes and structural proteins, in the muscle fibers.
- Increased muscle size and strength: The production of these enzymes and structural proteins leads to an increase in muscle size and strength.