Proviron! - Here's a topic we can debate..

[drab4]

I'm going a little off topic with this, but here are a couple of studies that I found quite interesting:




Effects of experimentally induced mild hyperthyroidism on growth hormone and insulin secretion and sex steroid levels in healthy young men.

Lovejoy JC, Smith SR, Bray GA, Veldhuis JD, Rood JC, Tulley R.

Pennington Biomedical Research Center, Baton Rouge, LA 70808-4124, USA.

Although triiodothyronine (T3) exerts major regulatory actions in both animals and humans, most clinical studies of T3 administration have been relatively short-term. The present study examined the effects of more than 2 months (63 days) of low-dose T3 treatment on overnight pulsatile growth hormone (GH) secretion, short-term insulin secretion, and of sex steroid levels in seven healthy, lean men studied at an inpatient metabolic unit. At baseline, there were strong correlations between sex hormone-binding globulin (SHBG) and several measures of GH production, including total GH production (r = .99), GH interburst interval (r = -.75), and GH mass (r = .82). SHBG was also inversely correlated with basal insulin secretion (r = -.74). There was a 42% increase in serum levels of total testosterone (18.5 +/- 1.3 to 26.3 +/- 1.8 nmol/L, P = .005) and a 150% increase in SHBG (18.0 +/- 2.2 to 44.9 +/- 7.0 nmol/L, P = .008) following T3 treatment. Estradiol and free testosterone levels were unchanged by treatment, although free testosterone decreased from 142.8 +/- 18.4 to 137.3 +/- 19.5 pmol/L. T3 treatment significantly reduced the GH interburst interval (P < .05) and produced slight increases in the measures of GH secretion. There were no statistically significant effects of T3 treatment on insulin secretion, although insulin peak amplitude, mass secreted per burst, and total production all decreased. We conclude that experimentally induced T3 excess in healthy men produces significant and sustained changes in sex hormone levels and GH secretion. Furthermore, there are strong associations between SHBG and both GH and insulin secretion independent of thyroid hormone excess that require additional study.




Synthesis and regulation of sex hormone-binding globulin in obesity.

Hautanen A.

Department of Clinical Chemistry, University of Helsinki, Finland. aarno.hautanen@sll.fimnet.fi

Sex hormone-binding globulin (SHBG) is a plasma glycoprotein with high binding affinity for testosterone and dihydrotestosterone and lower affinity for estradiol. SHBG is synthesized in the liver, and its plasma level is important in the regulation of plasma free and albumin-bound androgens and estrogens. Obesity and particularly excess visceral fat, known risk factors for cardiovascular and metabolic diseases, are associated with decreased testosterone levels in males and SHBG levels in both sexes. SHBG is usually positively correlated with high-density lipoprotein cholesterol and negatively correlated with triglyceride and insulin concentrations. A positive association between SHBG and various measures of insulin sensitivity has been demonstrated in both sexes, suggesting that decreased SHBG levels may be one of the components of the metabolic syndrome. We have examined pituitary-adrenocortical function, glucose tolerance, and lipoprotein and hormone levels in a large cohort of Finnish males. Abdominal obesity appears to be associated with slight hypocortisolemia and increased sensitivity to exogenous adrenocorticotropin stimulation, which may contribute to the hyperinsulinemia and related metabolic changes including decreased SHBG levels in males.





As we can see, SHBG levels seem to be strongly correlated with total test levels. High SHBG means high total test.

The effects of high SHBG on free test are minor. This makes sense because, as we have discussed, the body can only sense free test. However, we can see that with higher SHBG levels, there is a slight decrease in free available test. So during an extended "off" period, high SHBG will not necessarily be desirable. This is where a supplement such as discussed above might come in useful (or on cycle).

In addition high SHBG seems to increase GH production and also increase insulin sensitivity, a pleasant combination!

[Nelson Montana]

I still think you're missing a basic tenet here. SHBG is higher when total T is higher, but raising SHBG will not raise total T. That's the crux of the whole thing. And the fact that higher SHBG increases insulin sensitivity just means you're more prone to hold fat when SHBG is high.

[drab4]

SHBG is higher when total T is higher, but raising SHBG will not raise total T. That's the crux of the whole thing.

I still have to disagree mate, though I'll try not to cover too much old ground.

We've already agreed that free test is the important factor in determining feedback.

Thyroid hormones raise blood levels of SHBG by acting directly on the liver. This is well documented, I'll post some abstracts in a minute for reference.

As discussed previously, raising SHBG means there is less free test. So negative feedback is reduced. In response to this, more test is produced. So free test rises to approximate it's previous level.

Knowing this, I felt the first study helped show the mechanism by which total test was raised..... Higher levels of binding proteins.

And the fact that higher SHBG increases insulin sensitivity just means you're more prone to hold fat when SHBG is high.

Not necessarily mate. Higher insulin sensitivity generally means that you will produce less insulin. This would be likely to lead to lower bodyfat. Lean people are insulin sensitive. Obese people are insulin insensitive. Type 2 diabetics are of course highly insulin insensitive - and they often have low levels of SHBG.

[drab4]

Stimulation of sex hormone-binding globulin mRNA and attenuation of corticosteroid-binding globulin mRNA by triiodothyronine in human hepatoma cells.

Barlow JW, Crowe TC, Cowen NL, Raggatt LE, Topliss DJ, Blok RB, Stockigt JR.

Ewen Downie Metabolic Unit, Alfred Hospital, Melbourne, Victoria, Australia.

We examined the time course and dose response of the triiodothyronine (T3) effect on mRNAs for sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) in cells of the human hepatoma line HepG2. After 7 h of exposure to a saturating dose of T3, SHBG mRNA was unchanged but increased to 1.5 +/- 0.1 times the unstimulated control at 22 h. Maximal stimulation (2.3 +/- 0.6) was observed at 2-3 days. Corticosteroid-binding globulin mRNA was unchanged for 22 h after exposure to T3 but diminished thereafter to 64% by day 3. At 3-4 days of exposure, the changes in both SHBG mRNA and CBG mRNA were dose-responsive to the T3 concentration. For both mRNAs, half-maximal response occurred between 10 and 20 pmol/l bioavailable T3. Cortisol-binding proteins secreted by HepG2 cells after 3 days in culture also were T3 dose-responsive. No re-uptake of secreted CBG by the cells was observed, suggesting that the T3 effect on CBG secretion occurs during production of the mature protein. These data suggest that T3 stimulates the expression of the SHBG gene and attenuates the expression of the CBG gene. The effects of T3 on these genes are consistent with the increase in circulating SHBG and decrease in circulating CBG observed in hyperthyroidism. The HepG2 cells may be a useful human cell line in which to study the diversity of the molecular mechanisms of T3 action.




Regulation of production and secretion of sex hormone-binding globulin in HepG2 cell cultures by hormones and growth factors.

Loukovaara M, Carson M, Adlercreutz H.

Department of Clinical Chemistry, University of Helsinki, Meilahti Hospital, Finland.

Regulation of the production and secretion of sex hormone-binding globulin (SHBG) was investigated in HepG2 cell cultures by measuring SHBG protein concentrations intra- and extracellularly and studying changes in SHBG messenger ribonucleic acid levels. Insulin (10 nmol/L), insulin-like growth factor-I (15 nmol/L), and epidermal growth factor (20 nmol/L) decreased SHBG levels in parallel both intra- and extracellularly. Ten nmol/L 17 beta-estradiol, 10 nmol/L testosterone, and 100 nmol/L to 1 mumol/L cortisol increased SHBG levels inside the cells, but did not increase its release into the culture medium. Two hundred and fifty to 500 nmol/L 17 beta-estradiol and 500 nmol/L to 1 mumol/L testosterone increased SHBG levels intra- and extracelularly, but relative to control values, the increase was considerably greater inside the cells. T3 (10 nmol/L) increased SHBG levels, but unlike the effect seen with steroids, the increase was equally evident within the cells and the medium. Northern hybridization showed that insulin decreased and 17 beta-estradiol and T3 increased SHBG messenger ribonucleic acid levels marginally. The variable secretion of SHBG is hypothesized to be due to the different effects of hormones and growth factors on either the glycan moiety of SHBG or the expression of the alternatively spliced transcripts of the SHBG gene.

[Douro]

great post!

[pigmeat]

Bump! This is an old thread, but one of the most informative ones in the archives. Lots of new members that havent seen.

[3Vandoo]

wow, long time I didnt see something like that here

[Extranero]

Why isn't there a sticky on this?!? Good stuff.

[pigmeat]

Re: Proviron! - Here's a topic we can debate..

Lets bump this one to the top AGAIN!!!! Happy reading people!

[AlmostThere]

Re: Proviron! - Here's a topic we can debate..

Bump

[rado]

Re: Proviron! - Here's a topic we can debate..

This thread is old....I remember this tool here, JA

[pigmeat]

Re: Proviron! - Here's a topic we can debate..

JA, knows his shit...no doubt about it. He just liked to give you and YellowJacket a hard time, Rado!

[ELLAS]

Re: Proviron! - Here's a topic we can debate..

Good points on both sides here. Let me share my with everyone my own experience with proviron. Recently, about 5 weeks ago I started developing nodules at my nipples and were severely tender. I started a 5 month cycle of 1 gram enthanate and 600 mgs tren a week. I was in my third month when the gyno started. Now I was not taking any anti-e's during cycle. When the gyno started I took 20mgs nolva with 25 mgs proviron and the results were quite pleasant. With in 10 days all signs of gyno were gone and my strength went up on all areas about 10-15%. I got alot leaner, harder, and yes Vascular. When people at the gym notice and tell you these comments you know youre doing something right. So, I agree with Juice authority in the sense that I killed two birds with one stone.
Now, the reason I wasnt on nolva the entire time or an anti-e is because I make better gains with out them and I have a very low affinity for converting test into estrogen. In the ppast I have used anti-e's with my cycle but never nolva and proviron together.
Just my two bits in this topic.

[rado]

Re: Proviron! - Here's a topic we can debate..

Yea I know...I don't care anymore anyway, I'm much different now than when I 1st came to the boards 4-5 years ago....