SHBG Gene Polymorphisms and Serum Testosterone

If you get a second, take a look at this study. I think its very interesting. Ultimately there are three polymorphisms identified that affect SHBG binding affinty for testosterone. Having multiple versions of these can result in low serum testosterone levels. My question is, does this low binding affinity result in more aromatization and/or conversion to DHT given that more T is unbound to protein? If so, this could be a huge reason for estrogen dominance in some males, and for some men with low serum T.

And a question for any thyroid buffs...does thyroid function affect SHBG production?

http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002313

Id like to know this as well...
Im also curious are there any identifiable traits in the physical that hint of low shbg, because thats
always been something that made sense to me that was of particular concern for my hair loss. How many of you have had this tested?
Is there other ways of increasing shbg besides green tea and iodine, and also could an iodine deficiency cause unnecessarily low shbg>?

I want to say that T3 is necessary for the production of SHBG, but I'm not positive. If so, an iodine deficiency might exacerbate the problem. But considering these polymorphisms aren't that uncommon, if they are exposing T to increased aromatization and conversion to DHT, it could play a big role in many people's hairloss.

May be slightly off subject, but something else Ive recently thought about has anyone ever added iodine to their topical oils? I have read on the net before about how topical application of iodine could be beneficial, and has me considering shaking up several drops in my current topical mixture in my sig that I use every other day or so...

Back onto shbg, this is the last area known to me that I haven't really understood yet in the mpb discussion.
I am still finding much conflicting info regarding green tea increasing shbg and improving hair when some reviews say it increases dht/test and is negative to hair growth.Ive read black tea is beneficial in lowering dht by some large percentage though, but not sure if that's credible.
High fat diets also made more sense to me that they lowered shbg/ increased free testosterone ( carnivorous animals would be more aggressive right) I hope some informed members can jump into this subject here...

Something else I found
http://www.cenegenicsfoundation.org/library/library_files/Exercise_increases_serum_testosterone_and_sex_hormone_binding_globulin_levels_in_older_men.pdf_.pdf

http://www.ncbi.nlm.nih.gov/pubmed/11931850

Structure-activity relationships for inhibition of human 5alpha-reductases by polyphenols.
Hiipakka RA, Zhang HZ, Dai W, Dai Q, Liao S.
Source

Department of Biochemistry and Molecular Biology, The Ben May Institute for Cancer Research, and The Tang Center for Herbal Medicine Research MC6027, University of Chicago, 5841 S. Maryland, Chicago, IL 60637, USA.
Abstract

The enzyme steroid 5 alpha-reductase (EC 1.3.99.5) catalyzes the NADPH-dependent reduction of the double bond of a variety of 3-oxo-Delta(4) steroids including the conversion of testosterone to 5 alpha-dihydrotestosterone. In humans, 5 alpha-reductase activity is critical for certain aspects of male sexual differentiation, and may be involved in the development of benign prostatic hyperplasia, alopecia, hirsutism, and prostate cancer. Certain natural products contain components that are inhibitors of 5 alpha-reductase, such as the green tea catechin (-)-epigallocatechin gallate (EGCG). EGCG shows potent inhibition in cell-free but not in whole-cell assays of 5 alpha-reductase. Replacement of the gallate ester in EGCG with long-chain fatty acids produced potent 5 alpha-reductase inhibitors that were active in both cell-free and whole-cell assay systems. Other flavonoids that were potent inhibitors of the type 1 5alpha-reductase include myricetin, quercitin, baicalein, and fisetin. Biochanin A, daidzein, genistein, and kaempferol were much better inhibitors of the type 2 than the type 1 isozyme. Several other natural and synthetic polyphenolic compounds were more effective inhibitors of the type 1 than the type 2 isozyme, including alizarin, anthrarobin, gossypol, nordihydroguaiaretic acid, caffeic acid phenethyl ester, and octyl and dodecyl gallates. The presence of a catechol group was characteristic of almost all inhibitors that showed selectivity for the type 1 isozyme of 5 alpha-reductase. Since some of these compounds are consumed as part of the normal diet or in supplements, they have the potential to inhibit 5 alpha-reductase activity, which may be useful for the prevention or treatment of androgen-dependent disorders. However, these compounds also may adversely affect male sexual differentiation.


in other words, i seriously doubt that green tea would contribute to your hair loss.

J987 wrote:
Is there other ways of increasing shbg besides green tea and iodine, and also could an iodine deficiency cause unnecessarily low shbg>?

The aim of this study was to evaluate the effect of supplementing healthy men with soy isoflavones on the serum levels of sex hormones implicated in prostate cancer development. A total of 28 Japanese healthy volunteers (18 equol producers and 10 equol non-producers) between 30 and 59 years of age were given soy isoflavones (60 mg daily) supplements for 3 months, and the changes in their sex hormone levels were investigated at the baseline and after administration. The serum and urine concentrations of daidzein, genistein, and the levels of equol in the fasting blood samples and 24-h stored urine samples were also measured. All 28 volunteers completed the 3-month supplementation with isoflavone. No changes in the serum levels of estradiol and total testosterone were detected after 3-month supplementation. The serum levels of sex hormone-binding globulin significantly increased, and the serum levels of free testosterone and dihydrotestosterone (DHT) decreased significantly after 3-month supplementation. Among the 10 equol non-producers, equol became detectable in the serum of two healthy volunteers after 3-month supplementation. This study revealed that short-term administration of soy isoflavones stimulated the production of serum equol and decreased the serum DHT level in Japanese healthy volunteers. These results suggest the possibility of converting equol non-producers to producers by prolonged and consistent soy isoflavones consumption.Prostate Cancer and Prostatic Diseases advance online publication, 14 July 2009; doi:10.1038/pcan.2009.10.

I tried soy isoflavones and got the same sides as when I was on fin, looked like it was working (but I had to stop because of the sides). the same with green tea, that works as well in my exp. I would like to try natto, but it is hard to find in Europe.

Isn't low iodine -> less T3 -> less progest -> more estradiol -> more SHBG?

Anthony have you found any good aromatase inhibitors? i have read black tea catechins are better than green tea in this regard. quercetin shows some effect but only at the higher dosing end. chysin is apparantly big in the body building community, but it didnt hold up in the current in-vivio experiments. likely an issue with low bioavailability in the body even tho it shows good effect in vitro.

LoT,

I was optimistic at one point about the natural aromatase inhibitors but there just isn't much research to show they're that effective, and many of them actually act as estrogens, like quercetin.

This study shows no effect of quercetin, but it does show that chrysin was effective.
http://www.sciencedirect.com/science/article/pii/096007609390228O

But this study shows that in the doses practical for oral supplementation, Chrysin has no effect on testosterone levels. We expect it would if it was truly influencing aromatase.
http://online.liebertpub.com/doi/abs/10.1089/109662003772519967

I think you're right. It has to do with the bioavailability. I've heard that piperine increases absorption, but again, I just think it would require an obscene dosage and I wouldn't be comfortable given the possibility of other effects. For now, the only thing I'm confident lowers aromatase with minimal to no sides is an Rx inhibitor like arimidex.

anthonyspencer54 wrote:If you get a second, take a look at this study. I think its very interesting. Ultimately there are three polymorphisms identified that affect SHBG binding affinty for testosterone. Having multiple versions of these can result in low serum testosterone levels. My question is, does this low binding affinity result in more aromatization and/or conversion to DHT given that more T is unbound to protein? If so, this could be a huge reason for estrogen dominance in some males, and for some men with low serum T.

And a question for any thyroid buffs...does thyroid function affect SHBG production?

http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002313

I believe for the most part, it's a case of thyroid function. Iodine sufficiency will help normalize SHBG levels and keep estrogen at bay.

Regarding green tea. If I had a dollar for every time I saw this question, I would have a lot of money to burn. I've been using EGCG for a steady 8 years. It is quite safe (no hair loss).