5AR Question

[wookster]

Question: Exactly how is the 5 alpha reductase type 2 enzyme produced in the hair follicle structure?

 

[Bryan]

I'm not sure what kind of an answer you're looking for. It's a cellular protein that's coded for by a couple of different genes, and is produced by the cellular machinery like any other protein.

Bryan

 

[wookster]

I'm not sure what kind of an answer you're looking for. It's a cellular protein that's coded for by a couple of different genes, and is produced by the cellular machinery like any other protein.

Bryan

I am trying to visualize this structure you are talking about. Not an easy task...

http://www.sciencedaily.com/releases/20 ... 080003.htm

Nuclear receptors are ligand-activated transcription factors contained in cells. When activated by specific small molecules, the nuclear receptors initiate a complex process that results in gene expression.

 

[wookster]

http://en.wikipedia.org/wiki/Transcription_(genetics)

Transcription (genetics)
From Wikipedia, the free encyclopedia

Transcription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. Or, in other words, the transfer of genetic information from DNA into RNA. In the case of protein-encoding DNA, transcription is the beginning of the process that ultimately leads to the translation of the genetic code (via the mRNA intermediate) into a functional peptide or protein.

http://en.wikipedia.org/wiki/Androgen_receptor

In some cell types testosterone interacts directly with androgen receptors while in others testosterone is converted by 5-alpha-reductase to dihydrotestosterone, an even more potent agonist for androgen receptor activation. Examples are derivatives of the Wolffian duct for the former, and derivatives of the urogenital sinus, the urogenital tubercle, and hair follicles for the latter.

What is the chemical that tells the cells to produce 5 alpha reductase? :hairy:

 

[Bryan]

What is the chemical that tells the cells to produce 5 alpha reductase? :hairy:

What makes you think that there IS a specific chemical that tells cells to produce it?

There's evidence that the gene that produces the type 2 version (but not the type 1 version) is sensitive to androgens (testosterone was found to increase the production of type 2 mRNA within human scalp hair follicle cells in vitro), but my guess is that the enzyme is still produced at least to some extent on a regular basis, even in the absence of androgens.

Bryan

 

[wookster]

What is the chemical that tells the cells to produce 5 alpha reductase? :hairy:

What makes you think that there IS a specific chemical that tells cells to produce it?

There's evidence that the gene that produces the type 2 version (but not the type 1 version) is sensitive to androgens (testosterone was found to increase the production of type 2 mRNA within human scalp hair follicle cells in vitro), but my guess is that the enzyme is still produced at least to some extent on a regular basis, even in the absence of androgens.

Bryan

http://home.earthlink.net/~drfelman/notes.html


quote:

5-alpha-reductase

5-alpha-reductase is associated with the nuclear membrane and is found in high concentrations in male reproductive tissues, skin, and liver. Two isoenzymes (type 1 and 2) of 5-alpha-reductase have been identified in human tissue, these enzymes have only 50% homology in amino acid sequences. The gene for the type 1 isoenzyme is located on the short arm of chromosome 5, while the gene for the type 2 isoenzyme is located on the short arm of chromosome 2.



So it seems that the testosterone enters the cell and interacts with the 5 alpha reductase near the nuclear mebrane of cells? then the T to DHT conversion takes place, and the DHT then somehow instructs the cells to
inevitably generate growth factors for beard hair follicles and degrowth factors for scalp hair follicles?

 

[Bryan]

So it seems that the testosterone enters the cell and interacts with the 5 alpha reductase near the nuclear mebrane of cells?

The 5a-reductase enzyme is strongly membrane-bound, so that must happen AT the membrane. Furthermore, there seems to be some uncertainty about which membrane(s) contain the enzyme. Liang & Liao in their fatty acid study mention both the nuclear membrane and the endoplasmic reticulum membrane as the repository of the enzyme.

then the T to DHT conversion takes place, and the DHT then somehow instructs the cells to inevitably generate growth factors for beard hair follicles and degrowth factors for scalp hair follicles?

Yep. You got it.

Bryan