Mechanism of Male Pattern Balding?

Can you explain more in detail the actual mechanism of MPB? I know that some hair follicles are sensitive to DHT and somehow the DHT causes miniaturization, but how does this actually work? Also, any wisdom on why some hairs develop later in life even where there were no (or not visible?) follicles. Like pubic hair and hairs on the chest and back as men age? I am not going to write a book to...

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