Intracrine and Myotrophic Roles of 5α-Reductase and Androgens

The document reviewed the roles of 5α-reductase and androgens in muscle development and maintenance, emphasizing that skeletal muscle can synthesize bioactive androgens like testosterone and DHT from DHEA, and that exercise increases the expression of androgen-biosynthesizing enzymes in muscle. It highlighted that testosterone increases muscle mass and strength dose-dependently, while DHT has a lesser effect despite its higher affinity for androgen receptors. The review discussed the impact of 5α-reductase inhibitors, noting that finasteride did not impede muscle development, but dutasteride did, suggesting a critical role for DHT in muscle growth. The potential of selective androgen receptor modulators (SARMs) to provide anabolic effects in muscle and bone while minimizing adverse effects in non-target tissues was also noted. The document concluded that further research is needed to understand the specific roles of 5α-reductase isozymes and locally produced androgens in muscle.