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The Androgen Role in Male Hair Loss: Androgens play a significant role in male pattern hair loss. Historical observations by anatomist James Hamilton revealed that men who were castrated didn't exhibit MAA unless they received testosterone supplements. However, when researchers compared the levels of several androgens like testosterone, dehydroepiandrosterone sulphate (DHEA), and free testosterone between individuals with and without MAA, there weren't consistent differences. Interestingly, some studies found higher levels of hormones such as cortisol and androstenedione in individuals with MAA, suggesting that MAA could be influenced by a variety of hormones. Despite these findings, it's crucial to note that even normal levels of androgens can cause hair loss in those genetically predisposed.

 

Further Insights into MAA: Patients with conditions like androgen-insensitivity syndrome and 5 alpha-reductase deficiency, where their response to androgens is impaired, don't experience baldness. This indicates that MAA might result from the activation of follicular androgen receptors by DHT. Additionally, individuals with a mutation in the androgen receptor gene (as seen in Kennedy's disease) exhibit a decreased likelihood of developing MAA. Notably, balding scalp areas have shown increased DHT levels compared to non-balding regions.

 

Understanding Androgen Activities: The skin and its related structures possess all the essential enzymes for androgen synthesis and metabolism, similar to major organs like the gonads and adrenal glands. The enzyme 5 alpha reductase is pivotal, converting testosterone into a more active form, DHT. Two key types of this enzyme have distinct functions and distributions in the body.

 

Type 1 5 alpha reductase: Found in various skin structures like sebaceous glands, hair follicles, and sweat glands. Despite its broad presence, its specific role remains unclear.

 

Type 2 5 alpha reductase: Located primarily in the dermal papilla and other hair-related areas, it's responsible for the majority of DHT in the circulation.

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Additional Enzymatic Roles: Recent studies have highlighted several enzymes that could contribute to MAA. For instance, enzymes like 17-beta- and 3-beta-hydroxysteroid dehydrogenases (HSD) collaborate with type 2 5 alpha reductase to convert testosterone to DHT. To maintain balance, certain enzymes produce potent androgens, while others work to neutralize excess androgens.

 

Androgens and Hair Growth: Androgens have varying effects on hair growth depending on the body area. While they promote hair growth in areas like the beard and armpits, they suppress hair growth on the scalp for some individuals. Research has suggested that this varying response might be determined by a secondary system within androgen-sensitive follicles.

 

Further Studies: Experiments have shown that hair follicles can self-regulate their androgen response. This self-regulation might explain why certain areas of the scalp are more susceptible to balding than others. In hair transplantation experiments, it was observed that hair resistance to MAA is intrinsic to each follicle, explaining why transplanted hairs behave similarly to their origin site.

 

In conclusion, while hormones, particularly androgens, play a crucial role in MAA, the exact mechanisms and the myriad factors contributing to hair loss are complex and still a subject of ongoing research.