I lifted this from http://www.definitivemind.com, Dr. Mariano’s blog/discussion forum:
[i]Here is a steroid biosynthesis chart that I created which helps clear up questions about the synthesis of various steroid signals. For the longest time, I wanted to create a clear chart since the existing ones are not very clear or easy to memorize. Even Jonathan Wright, M.D., who invented estrogen replacement therapy with Tri-Est more than 30 years ago, to this day, can’t remember his steroid tree well despite having a steel-trap memory, where he can remember things he read word-for-word 10 years ago.
What is so interesting is that so many of the enzymes are cytochrome P450 enzymes - which mean they are iron dependent. Thus if one is low in ferritin (a measure of iron available to cells, as opposed to iron already in hemoglobin or myoglobin), one may be impaired in steroid hormone biosynthesis.
Additionally, the 2-hydroxy and 4-hydroxy estrogens are degraded by catechol-O-methyl transferase, the same enzyme that degrades the catecholamines, such as norepinephrine. Thus under stress, more norepinephrine is made and competes with the estrogens for degradation, prolonging the duration of action of the more carcinogenic 4-hydroxy estrogens.[/i]
Steroid Signal Biosynthesis Pathways Chart by Dr. M
http://www.definitivemind.com/forums/showthread.php?t=58 (you’ll have to register to be able to DL the PDF; it’s too large to attach here; it’s VERY cool and worth the effort)
[i]I did the most important pathways to keep things clear - to allow clinicians to be clear headed. The actual pathways are much much more wildly complicated. For example, I left out all of the elimination pathways because there are a ton of them. There are also many side-tracks, etc. that are not as commonly clinically significant. There are also many intermediate structures, which aren’t as clinically useful but in some cases may be present. For example, it takes 5 steps for aromatase to transform testosterone to estradiol. The four intermediate products are not that useful to note.
I’ll probably add to the chart the progesterone metabolites created by 5-alpha-reductase since they are important in the brain. I missed them this go-round.[/i]
Here are some basic links if you want to boggle your mind:
http://www.genome.jp/kegg/pathway/map/map00140.html
http://www.genome.jp/kegg/pathway/map/map00150.html
http://www.genome.jp/dbget-bin/show_…ko00100+C00187
If this stuff interests you, there are also stickies on adrenal insufficiency, iron deficiency, Thyroid Hormone, the Blood Brain Barrier, and the Brain, Hormone Lab Pointers, etc. from Dr. Mariano.
Stickies section (register to be able to view everything):
http://www.definitivemind.com/forums/forumdisplay.php?f=22 (more in-depth discussion + links to more pathway maps).