11-26-2007, 09:20 PM
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Registered User
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Join Date: Nov 2002
Location: Scottsdale, Arizona
Posts: 10,626
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Quote:
Originally Posted by Pete Geither
Balding ? I was naturally interested in the link, but apparently, there is none.
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Scientists still have a limited understanding of why androgenetic alopecia--commonly known as male-pattern baldness--occurs in the first place. It seems to result from three interdependent factors.
The first was uncovered more than two millenniums ago when the ancient Greeks noted that eunuchs did not go bald. They surmised correctly that among the things lost in castration was the mechanism that leads to baldness. The missing variable, it turns out, is male hormones. Scientists have learned since then that testosterone is only an accomplice, not an originating agent, in the balding process.
The second, and most important, variable is a genetic predisposition for hair loss. Researchers are convinced that baldness is hereditary, but they have yet to identify the genetic coding that makes the scalp go bare. Even with the right genes, hair loss only occurs with a third factor: aging. All men and women lose some hair as they get older, but those with pattern baldness lose more hair at a younger age than do their counterparts (pattern baldness affects nearly 40 percent of males in their 30s and well over half of all men over 50).
People with pattern baldness have genes that at a certain point trigger the creation of an enzyme called 5-alpha reductase. When it comes in contact with the testosterone that is typically present in a hair follicle, the enzyme creates an offshoot called dihydrotestosterone (DHT), which causes the follicle to dry up. Each time a new hair sprouts from a root where DHT is present, it grows a little shorter and thinner. In time, the follicle becomes dormant and new hairs stop growing altogether. Where this process occurs on a human scalp is determined by the genes.
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