Dat's - CJC-1295 & GHRP-6 (Basic Guides)

DatBtrue said:

You asked a very good question.

From: Insulin Regulation of Human Hepatic Growth Hormone Receptors: Divergent Effects on Biosynthesis and Surface Translocation, Kin-Chuen Leung, Nathan Doyle, Mercedes Ballesteros, Michael J. Waters, And Ken K. Y. Ho, The Journal of Clinical Endocrinology & Metabolism 2000 Vol. 85 No. 12 4712-4720

In the study they recognized the importance of insulin and how it interacts with growth hormone, specifically highlighting that "insulin is essential for GH stimulation of IGF-I production and growth."

They then focused on the results of their study. They found that:

- Insulin up-regulated total and intracellular GH-receptors in a concentration-dependent manner.

- The abundance of GHR messenger ribonucleic acid and protein, ... respectively, markedly increased with insulin treatment.

[So the more insulin that was used the more biosynthesis or creation of GH-receptors that occurred. Now these receptors while abundant were not necessarily moved to the surface of the cell nor where they activated. Just a pool of GHRs was created.]

CAVEAT: Parts of the GH-Receptor can move to the nucleus and mediate gene expression. See the wonderful post that follows on "Growth Hormone Receptor structure, post-biogenesis behavior and degradation"
​

- It increased surface GHRs in a biphasic manner, with a peak response at 10 nmol/L, and modulated GH-induced Janus kinase-2 phosphorylation in parallel with expression of surface GHRs.

[So insulin increases the number of GH-receptors that make it to the cell surface AND increase the "intensity" of activation...but up to a point. After that point is reached insulin begins to hinder both the number of GH-receptors and "intensity" of activation"]

To quote from the study on this point:

Insulin induced a concentration-dependent increase in GHR biosynthesis, but simultaneously inhibited surface translocation. However, the net effect of reducing receptor surface availability only occurred at concentrations greater than 10 nmol/L, a concentration causing 70% inhibition of surface translocation. These data suggest that up-regulation of surface GHRs can occur with as little as 30% of intracellular receptors available for translocation to the cell surface. At concentrations above 10 nmol/L, the inhibitory effect of insulin on surface translocation overrides the compensatory effect of a 4- to 5-fold increase in receptor biosynthesis.​

[So this means that insulin increases GH-receptors by 400-500% but that as insulin rises it reduces the number of those GH-receptors that make it to the surface and are active. There is a point at which insulin begins to reduce the benefit of this GH-receptor creation. That point is 10 nmol/L of insulin. Just prior to that point insulin has inhibited substantially the translocation of GH-Receptors but the increased quantity made up for it and created an overall net benefit.]

So the problem becomes how to translate that pivot point (10 nmol/L) into a number we can use.

From: Correspondence Letter Regarding Article by von Lewinski et al, "Insulin Causes [Ca2+]i-Dependent and [Ca2+]i-Independent Positive Inotropic Effects in Failing Human Myocardium", Chih-Hsueng Hsu, MD; Cheng-I Lin, PhD; Jeng Wei, MD, Circulation. 2005;112:e367

...we find that "3 IU/L, equivalent to 20 nmol/L" ...so 10 nmol/L is equivalent to 1.5 IU/L

From Wiki Answers **broken link removed**

...we find that humans have 5-6 litres of blood in general.

So 5 x 1.5 = 7.5IU
So 6 x 1.5 = 9IU​

Therefore the point at which the amount of insulin in plasma becomes a negative rather then a positive is approximately 7.5 to 9 IUs.

So to arrive at a net benefit an insulin amount below that threshold point such as 5-6 ius is desirable.

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So much for the Anti-Aging Medicine doctors out there who tell their patients who take GH in the morning to not eat until a couple hours after their shot.

Their reasoning (if you call it that LOL) is insulin blocks the IGF-1 receptor, even though the affinity for same is 2 to 3 orders of magnitude less (at appropriate serum concentrations) than it is for IGF-1.

Applying Farmer's Logic, how long would it be then since you last ate?

You need SOME insulin (but not too much), like it is for estrogen.

Datbtrue said:

Three spots of GHRP-6 at saturation dose per day probably gives the equivalent of 2 to 2.5iu of GH per day (guesstimation).

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Wise Guy said:

I take it that is irrespective of GHRH use?

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Bump, and Swale, I'd love to see the results you have had. Post em up

Wise Guy said:

Bump, and Swale, I'd love to see the results you have had. Post em up

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I'll be glad to. Here and our humble little forum. It's surprising how much it takes to just put some lab values from patients on a spread sheet. LOL But at least we'll have rock solid info for everyone, albeit at Anti-Aging Medicine dosages and results.

We're still compiling everything. But I'll have to pull it all together for presentation at A4M Orlando in April.

At this point, I'll just pass on that it is taking a bit longer than I would have expected to ramp up mRNA. Dat?

Wise Guy--does this mean you are going to stop pestering me about this now? LOL

Tell me what you guys think about this;

My wife is 46 and a national champion hevyweight bodybuilder. I am a retired world champion powerlifter (275's) and 52 years old. We are going to both use the CJC 1295 and GHRP-6. We both want some muscle growth, drop some BF and slow or reverse aging.

Myself:
100 mcg CJC 1295 with 100 mcg GHRP-6, 2 x per day (morning/bedtime)

Wiife:
75 mcg CJC 1295 with 10 mcg GHRP-6, 2 x per day (morning/bedtime)

question about reconsitution

sorry

laskerja said:

GHRP-6 comes in 5mg vials. 5mg=5000mcg(right?). So if someone added 5ML of water to MG, each unit on a slin pin would be 100mcg. The problem is the vial is the same size as a growth vial, and only holds about 4ML MAX of water. How is someone supposed to do this?

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Don't think you should've posted this question in Dat's thread...Start a thread and I'll explain your errors...

SWALE said:

At this point, I'll just pass on that it is taking a bit longer than I would have expected to ramp up mRNA. Dat?

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IGF-I mRNA levels?

Human studies often show increasing levels of IGF-1 every month for three months before plateauing at a higher level.

How & where are you measuring mRNA?

Peripheral Tissue IGF-1 mRNA

I just happened to be reading a study * on Rats (I know, I know...I prefer mice) that examined mRNA levels for IGF-1 in the brain following either GHRP-6 or GH administration. They found:


Method: Infusion of GH at 100 µg/d OR infusion of GHRP-6 at 150 µg/d.


* Growth Hormone (GH) and GH-Releasing Peptide-6 Increase Brain Insulin-Like Growth Factor-I Expression and Activate Intracellular Signaling Pathways Involved in Neuroprotection, Laura M. Frago, Endocrinology Vol. 143, No. 10 4113-4122 2002

Adipose Visceral Fat Negatively correlated with effectiveness of GHRH & GHRP-2

Presented at ENDO 08 Annual Meeting (Ednocrine Society Annual Meeting)

Joint Regulation of Pulsatile GH Secretion by Estradiol, Dihydrotestosterone and Abdominal Visceral-Fat Mass in Healthy Older Men: A Paradigm of Aromatase and 5-alpha-Reductase Types I and II Blockade, J Veldhuis, K Mielke, J Miles, C Bowers

Background Dissecting the relative roles estradiol (E2), 5-alpha-dihydrotestosterone (DHT), and abdominal visceral fat mass (AVF) in the specific mechanistic regulation of GH secretion remains difficult. In part the impasse reflects interdependency among Te-derived sex steroids due to interconversion by aromatization and 5-alpha reduction, and in part the separate but interactive nature of hypothalamo-pituitary pathways driving (GHRH and ghrelin/GHRP-2) or inhibiting (somatostatin-14, SS-14) GH secretion.

Subjects Eleven healthy men ages 61-79 yr.

Methods Subjects were each studied 5 times fasting on separate mornings in random order. Secretagogues comprised saline, SS-14 withdrawal, bolus GHRH or GHRP-2, and L-arginine infusion followed by bolus injection of both peptides (to estimate maximal pituitary GH secretion).

AVF (adipose visceral fat) estimates were made by single-slice CT scan.

Outcomes

Regression analyses revealed that unstimulated GH secretion was most strongly determined by AVF (standardized coefficient, sc = -0.648, P = 0.031).

SS-14 withdrawal-induced GH release tended to correlate with E2 (sc = +0.589, P = 0.071).

The response to GHRH bolus was strongly determined by AVF (sc = -0.712, P = 0.014) and weakly by DHT (sc = +0.596, P = 0.053).

In contrast, GH peaks induced by GHRP-2 and triple-secretagogue infusions were associated with only AVF (sc = -0.689, P = 0.019).

Summary E2 and DHT are positively predictive of GH responses to specific, rather than all, secretagogues, whereas AVF is negatively correlated with GH responses to all secretagogues except SS-14 withdrawal.

Conclusion Sex steroids specifically and visceral adiposity generally determine peptide-selective drive of GH secretion in healthy older men. The precise pathways that mediate the interdigitating mechanisms are not known.

Effect of Adipose Visceral Fat (AVF) on peak GH concentrations

DatBtrue said:

IGF-I mRNA levels?

Human studies often show increasing levels of IGF-1 every month for three months before plateauing at a higher level.

How & where are you measuring mRNA?

Peripheral Tissue IGF-1 mRNA

I just happened to be reading a study * on Rats (I know, I know...I prefer mice) that examined mRNA levels for IGF-1 in the brain following either GHRP-6 or GH administration. They found:

"Treatment of adult male rats with GHRP-6 or GH for 1 wk significantly increased IGF-I mRNA levels in the hypothalamus, cerebellum, and hippocampus, with no effect in cerebral cortex."​

Method: Infusion of GH at 100 µg/d OR infusion of GHRP-6 at 150 µg/d.

View attachment 24231​

* Growth Hormone (GH) and GH-Releasing Peptide-6 Increase Brain Insulin-Like Growth Factor-I Expression and Activate Intracellular Signaling Pathways Involved in Neuroprotection, Laura M. Frago, Endocrinology Vol. 143, No. 10 4113-4122 2002

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I'm sorry; I should have been more specific. I meant GH mRNA.

And I know some folks who qualify as your favorite test subjects. LOL

DatBtrue said:

Presented at ENDO 08 Annual Meeting (Ednocrine Society Annual Meeting)

Joint Regulation of Pulsatile GH Secretion by Estradiol, Dihydrotestosterone and Abdominal Visceral-Fat Mass in Healthy Older Men: A Paradigm of Aromatase and 5-alpha-Reductase Types I and II Blockade, J Veldhuis, K Mielke, J Miles, C Bowers

Background Dissecting the relative roles estradiol (E2), 5-alpha-dihydrotestosterone (DHT), and abdominal visceral fat mass (AVF) in the specific mechanistic regulation of GH secretion remains difficult. In part the impasse reflects interdependency among Te-derived sex steroids due to interconversion by aromatization and 5-alpha reduction, and in part the separate but interactive nature of hypothalamo-pituitary pathways driving (GHRH and ghrelin/GHRP-2) or inhibiting (somatostatin-14, SS-14) GH secretion.

Subjects Eleven healthy men ages 61-79 yr.

Methods Subjects were each studied 5 times fasting on separate mornings in random order. Secretagogues comprised saline, SS-14 withdrawal, bolus GHRH or GHRP-2, and L-arginine infusion followed by bolus injection of both peptides (to estimate maximal pituitary GH secretion).

AVF (adipose visceral fat) estimates were made by single-slice CT scan.

Outcomes

Regression analyses revealed that unstimulated GH secretion was most strongly determined by AVF (standardized coefficient, sc = -0.648, P = 0.031).

SS-14 withdrawal-induced GH release tended to correlate with E2 (sc = +0.589, P = 0.071).

The response to GHRH bolus was strongly determined by AVF (sc = -0.712, P = 0.014) and weakly by DHT (sc = +0.596, P = 0.053).

In contrast, GH peaks induced by GHRP-2 and triple-secretagogue infusions were associated with only AVF (sc = -0.689, P = 0.019).

Summary E2 and DHT are positively predictive of GH responses to specific, rather than all, secretagogues, whereas AVF is negatively correlated with GH responses to all secretagogues except SS-14 withdrawal.

Conclusion Sex steroids specifically and visceral adiposity generally determine peptide-selective drive of GH secretion in healthy older men. The precise pathways that mediate the interdigitating mechanisms are not known.

Effect of Adipose Visceral Fat (AVF) on peak GH concentrations

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Dat, this is very interesting. The more AVF, the less an impact GHRH/GHRP has on plasma [GH]. In other words, the leaner you are, the stronger the GH eliciting response the GHRH/GHRP will have.

Also, the data tells us which peptide results in greater GH response: GHRP! So if you're going to purchase one or the other, go with GHRP. The pricey (perceived to be more powerful) GHRH is not the better option.

Of course, the ideal situation is to run both as you'll experience a significant increase in plasma [GH] vs. running GHRP solo.

Dat, does the full study provide any translation bewteen AVF (X-axis value) and body fat%?

SWALE said:

I'll be glad to. Here and our humble little forum. It's surprising how much it takes to just put some lab values from patients on a spread sheet. LOL But at least we'll have rock solid info for everyone, albeit at Anti-Aging Medicine dosages and results.

We're still compiling everything. But I'll have to pull it all together for presentation at A4M Orlando in April.

At this point, I'll just pass on that it is taking a bit longer than I would have expected to ramp up mRNA. Dat?

Wise Guy--does this mean you are going to stop pestering me about this now? LOL

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Awesome, I will be looking forward to it.

Thanks -

Nick

papapumpsd said:

Dat, does the full study provide any translation bewteen AVF (X-axis value) and body fat%?

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The "fat pad" is measured by centimeters squared (cm2) to give precision and accurate comparison between amounts of visceral adipose tissue.

papapumpsd said:

Also, the data tells us which peptide results in greater GH response: GHRP! So if you're going to purchase one or the other, go with GHRP. The pricey (perceived to be more powerful) GHRH is not the better option.

Click to expand...

Well we know that already. GHRH illicits a weaker GH pulse in part because it has zero control over whether somatostatin is active. In fact if somatostatin is currently suppressing a GH wave (oversimplification) then administering GHRH may have no effect or very little on GH release.

GHSs (Ghrelin, the GHRPs (GHRP-6, GHRP-1, GHRP-2, Hexarelin, Ipamorelin), and the non-peptide molecules such as MK-677) all create a pulse of GH in part by inhibiting somatostatin (at the pituitary & hypothalamus), in part by binding to a GHS-receptor and using a distinct intracellular mode to compliment GHRH's mode on somatotroph GH secretion, in part by increasing GHRH release from the hypothalamus...

Even if you use some form of modified GRF(1-29) by itself you still need multiple administrations measured in milligrams (as opposed to micrograms) to get substantial effects.

For example the proprietary "GHRH Super Analogue" (which is probably not much different then the modified GRF(1-29) we use) being clinically tested * under the code name AKL-0707 required two administrations a day of 1.5mgs (for a 100kg man) to illicit an approximate 400% increase in GH and a 350% increase in IGF-1.

The measured increases were made after 28 days... so we can say that it took a month to climb to those increased levels.

So they used 10 times the amount we use (3mgs vs 300mcg/day) BUT we smartly administer a GHRP with it which helps us significantly approach their numbers.

* AKL-0707 GHRH Super Analogue Reverses Wasting in Patients with Chronic Kidney Disease, A Wiecek, S Niemczyk, E Zukowska-Szczechowska, K Zalecka, J Gorcznska, S Roetkegel, M Kubik, B Czerwienska, K Gosek, J Veldhuis, S Kay, H Sikorska, T Jouhikainen, F Schaefer, Clinical Trials Symposium at the Annual June 15-18, 2008 Meeting of the Endocrine Society

My NOTE: This GHRH super analog is elsewhere described as 29 amino acid GRF modified to protect it from proteolytic cleavage... so we are just talking about amino acid substitutions probably identical in part if not in whole to the modified GRF(1-29)/tetra-substituted GRF we use.

How GHRPs are cardio-protective


The growth hormone secretagogues (GHS) are a family of synthetic compounds originally selected for their potent and specific effects on GH release. Nonetheless, it has been reported by us and other researchers that the GHS have also many extraendocrine actions, including those on energy metabolism and cardiovascular function. Ghrelin, the endogenous GHS, specifically binds to the GHS-R1a, a receptor that has been proposed to mediate the biological activities of endogenous and synthetic GHS.

The activation of the GHS-R1a is not enough to explain the results that we have previously reported on the ability of hexarelin, a synthetic full agonist of the GHS-R1a, to protect the rat heart from the damage induced by the ischemia-reperfusion procedure. In fact, the GHS-R1a is not expressed in the myocardium, and ghrelin is much less effective than hexarelin in protecting the heart from ischemia-reperfusion damage.

Moreover, it has also been demonstrated that in the cardiovascular system hexarelin and other GHS can also bind to the CD36, a scavenger receptor.

Interestingly, a large similitude exists between the cardioprotective effects of hexarelin and those of some angiotensin-converting enzyme (ACE)-inhibitors. For this reason, we have decided to ascertain whether hexarelin, ghrelin and other synthetic GHS can modify the catalytic activity of serum and tissue ACE in rats and humans.

Briefly, 10 ul of serum or tissue homogenate were incubated in presence of hippuryl-histidyl-leucine, a substrate of ACE that is cleaved to histidyl-leucine. The cleavage of the substrate was quantified by measuring the fluorescence at 365/495 nm (excitation/emission) in presence of orthophthaldialdehyde. Enalapril was chosen as reference ACE-inhibitor.

Hexarelin (1 to 100 uM) dose-dependently blunted ACE activity up to about 50% in rat and human plasma and rat lung, heart and kidney. Enalapril (0.1 to 5 uM) dose-dependently inhibited ACE activity in serum and tissues up to 85%. Ghrelin (1 to 100 uM) did not significantly modify serum and tissue ACE activity at all the concentrations tested, whereas other synthetic GHS-R1a ligands demonstrated a dose-dependent inhibition of ACE activity ranging from 10 to 85%.

We conclude that the protective actions of certain GHS on the cardiovascular system might be mediated, at least in part, by the capability of these compounds to modulate the ACE activity in the general circulation and locally in tissues.

DatBtrue said:

Give it a try bro and you tell me.

There is a lot of wiggle room in precisely how to do things. Some of it is a little subjective.

The high dose of GH with a day off will be sufficient to resensitize everything...so that looks good. The insulin PWO will give the GH anabolic meaning on top of a base of testosterone which will do so many things.

Looks good.

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Thanks brother. Im still debating if im gonna run 100mcg T4 with it but my goal is mainly size and I havent seen a lot research stating the importance of using t4/t3 while on GH so maybe i'll hold off. What is gonna be nice is only 3shots per week. Im sick and tired of daily multiple shots

L-argneine

Swale or Dat, L-argenine has twice been mentioned in this thread but with no elaboration. Functions listed in Wiki look encouraging, but I would like to know if it can serve any useful purpose in an anti-aging regimen.

GHRH & GHRP-2 and GH mRNA & GH-R mRNA

SWALE said:

I'm sorry; I should have been more specific. I meant GH mRNA.

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The following is the majority of the discussion from, EXPERIMENTAL STUDY - Effect of GHRH and GHRP-2 treatment in vitro on GH secretion and levels of GH, pituitary transcription factor-1, GHRH-receptor, GH-secretagogue-receptor and somatostatin receptor mRNAs in ovine pituitary cells, Ming Yan, Maria Hernandez, Ruwei Xu and Chen Chen, European Journal of Endocrinology (2004) 150 235–242

Its a long read, but I posted it in full because it references relevant in vivo studies as well as their own findings to give us a picture of precisely how GHRH & GHRP-2 effect GH mRNA levels. The timing is interesting...

Note that Sermorelin's half-life comes up a little short....as perhaps 10 minutes is needed.

Solution? - maybe inject Sermorelin & GHRP-6 together, wait 6 minutes and inject another bit of Sermorelin.

Solution? - modify Sermorelin at the 2nd position (swap alanine for D-alanine)

The relevant timing points are highlighted below. As we would expect the combined GHRH (serum made GHRH longer-lasting) + GHRP-2 had the largest impact.

Of interest, GH-receptor mRNA is increased by GHRH immediately as is the GH ligand so it seems that synthesis of GH-receptor triggers early GH release. This point is very interesting to me.

Discussion
...
Pituitary GH secretion is, to a large extent, controlled by three regulatory hormones: GHRH, GHS and SRIF. Each binds to G-protein-coupled membrane receptors through which intracellular signalling systems are activated (1). GHRH and GHRP administration potently increases GH secretion and this is not altered by gender, adiposity or age (9). However, peripheral circulating GHRH levels are not usually linked to an increase in GH levels as evidenced in patients with hypothalamic GHRH-secreting tumors (33). The key cell type in the regulation of GH levels is the pituitary somatotrope, which determines the amount of GH secreted in response to hypothalamic GHRH stimulation. Combined GHRH and GHRP treatment plays an important role clinically, however, the data on the mechanism of GHRH/GHRH-R and GHRP/GHS-R action are controversial (19–21). The differences may relate to the duration of GHRH and GHRP treatment and cell culture conditions as well as animal age.

In this study, we investigated the mechanism of action of GHRH/GHRP using primary cultures of ovine pituitary cells treated with GHRH and GHRP-2 in vitro. The present study carefully investigated the concentration and duration of GHRH and GHRP treatment using 0.5, 1, 1.5 and 2 h time points and serum-free incubation conditions for cell culture to clarify the mechanism of GHRH/GHRH-R and GHRP/GHS-R action. Treatments with 10nM GHRH and 100nM GHRP-2 for 0.5, 1, 1.5 and 2 h were chosen in this study to investigate short- to mid-term changes in somatotropes. GHRH at 1.0 mg/kg (i.v.) in vivo maximally stimulated GH secretion at 15–45 min, with GH levels returning to baseline by 90–120 min after GHRH injection in humans (34). GHRP-2, GHRP-6, hexarelin or non-peptidyl GHRP mimetic compound (L-692, 429) treatment rapidly increases serum GH concentrations within 5–15 min, with the peak GH concentration usually observed 15–30 min after intravenous injection in humans (35, 36). The presence of serum in the culture medium maintains basal levels of the GHRH receptor and is important in long-term GHRH treatment (20). However, the biological half-life of GHRH 1–44 is about 3–6 min in vivo (37) as GHRH is rapidly inactivated by a plasma dipeptidyl aminopeptidase, producing a more stable metabolite, GHRH 3–44, which is about 1000 times less potent than the parent compound (37). The culture of ovine pituitary cells in serum-free culture conditions, as employed in this study, overcomes the quick degradation of GHRH and allows subsequent stimulatory GHRH and GHRP treatments to be performed under defined conditions (38).

GHRH and GHRP treatment for 15 and 30 min rapidly stimulates maximal GH release (34–36). Furthermore, GHRH treatment for as little as 10 min rapidly increased GH transcription rate by 200–300% in primary cultured pituitary cells (39, 40). To analyse the transcription regulation of GH, we examined GH mRNA levels in response to GHRH and GHRP-2. Our results show that treatment with GHRH, GHRP-2 and combinations of GHRH and GHRP-2 increased GH mRNA expression and GH release 0.5, 1.0, 1.5 and 2 h after treatment, in a time-dependent manner. The level of GH mRNA 0.5, 1, 1.5 and 2 h after treatment was greatest in the combined GHRH and GHRP- 2 treatment group rather than in the GHRH or GHRP-2 alone treatment groups. Our results are consistent with early reports that 10nM GHRH treatment of rat pituitary cells in serum-free medium increased GH mRNA expression by 1.8- and almost 2.0-fold at 0.5 and 1 h respectively (40). This demonstrates that the effects of GHRH, GHRP-2 and combinations of GHRH and GHRP-2 on GH mRNA expression are rapid and occur at GH gene transcription level (40).

GHRH and GHRP bind to their specific receptors on the membranes of somatotropes (37). GHRH stimulates GH synthesis by increasing the transcription rate of the GH gene and consequently GH release (40, 41). GHRP-2 enhances pituitary GH gene expression and directly stimulates GH release (42). Our results show that the duration of GHRH or GHRP-2 treatment influences the effects on the corresponding receptor mRNA expression and GH release. GHRH and GHRP treatment for 1.5 h reduces their own receptor mRNA levels. These results are consistent with previous reports which suggest that GHRH in the short-term suppresses its own receptor expression (8, 20). Surprisingly, in this experiment, the short-term GHRH or GHRP treatment (0.5 h) significantly increased the expression of ligand-specific receptor mRNAs, and also increased GH release from ovine pituitary cells. This suggests that GHRH-R or GHS-R mRNA expression may contribute to the increase in GH secretion. GHRH treatment does not significantly influence the mRNA level of GHS-R, nor does GHRP-2 change GHRH-R expression with short-term treatment. The results supported our previous report suggesting that GHRP-2 does not act through the GHRH receptor (6). It is worth mentioning that another study indicated that GHRH, at any dose tested, did not affect GHS-R levels in vitro (8).

GH expression is mainly controlled by Pit-1, a member of the homobox POU (representing a homeodomain protein family of which the founder members are Pit-1, Oct 1/2 and Unc-86) family of DNA-binding proteins, and GHRH and GHRP-2 elicit a time-dependent activation of Pit-1 expression by anterior pituitary cells (1, 35). Our results indicate that with combined GHRH and GHRP-2 treatment, Pit-1 mRNA expression is increased to 150, 121 and 168% at 0.5, 1.5 and 2 h after treatment respectively. GHRH enhances the levels of Pit-1 mRNA expression 0.5, 1, 1.5 and 2 h after treatment. GHRP-2 also significantly increases the levels of Pit-1 mRNA 0.5 and 2 h after treatment. GHRH and GHRP-2 may activate Pit-1 transcription and stimulates GH expression in pituitary cells through mediation of protein kinase C (PKC), mitogen-activated protein (MAP) kinase and PKA activation (1, 13, 14, 43).

Somatostatin binds to a family of specific receptors and inhibits adenylyl cyclase via Gi proteins, and inhibits GH release but not its biosynthesis (44). In addition, somatostatin may potentially play (dual) inhibitory and stimulatory roles in controlling GH secretion by acting on two distinct somatotrope cell populations in the porcine pituitary (45). Five somatostatin receptor subtypes have been cloned and characterized and their expression is regulated in a subtype and tissue-specific manner (46–48). The results of GHRH action on sst receptor synthesis shows that, in vivo, a 4 h GHRH infusion and, in vitro, a 4 h 10nM GHRH treatment of rat pituitary cells increased sst-1 and sst-2 mRNA levels but decreased sst-5 mRNA levels (26). In the current study, 10 nM GHRH treatment increased sst-1 mRNA expression 0.5 to 2 h after the treatment. Although GHRH also increased sst-2 mRNA expression this was not statistically significant. This suggests that the acute direct regulatory action of GHRH on the synthesis of sst-1 and sst-2 receptor subtypes may be time-dependent. GHRH increased sst-1 mRNA expression may be partially due to GHRH-induced increases in Pit-1 mRNA, which activates pituitary sst-1 mRNA expression (14, 49). In contrast, 100nM GHRP-2 reduced sst-1 and sst-2 mRNA expression 0.5 to 2 h after treatment. GHRP has been suggested to act as a functional SRIF antagonist (11). Inhibition of the SRIF receptors including sst-1 and sst-2 by GHRP-2 supports this view.

In summary, the results of this study indicate that GHRH and GHRP-2 are important mediators regulating GH, GHRH-R, GHS-R, Pit-1, sst-1 and sst-2 mRNA expression, and GH synthesis. Effects on somatotropes manifest as either a priming or an inhibitory modification of the cells, leading to increased or decreased GH secretion. Moreover, the results demonstrate that GHRH and GHRP regulate their receptor synthesis and GH release in a time-dependent manner. This study represents an essential step forward in understanding the influence of GHRH and GHRP on somatotropes. Application of this understanding may aid the development of new GHSs with high efficacy.

Selected References

37 Frohman LA & Kineman RD. Growth hormone-releasing hormone and pituitary somatotrope proliferation. Minerva Endocrinology 2002 27 277–285.

38 Gick GG, Zeytin FN, Brazeau P, Ling NC, Esch FS & Bancroft C. Growth hormone-releasing factor regulates growth hormone mRNA in primary cultures of rat pituitary cells. PNAS 1984 81 1553–1555.

39 Barinaga M, Yamonoto G, Rivier C, Vale W, Evans R & Rosenfeld MG. Transcription regulation of growth hormone gene expression by growth hormone-releasing factor. Nature 1983 306 84–85.

40 Barinaga M, Bilezikjian LM, Vale WW, Rosenfeld MG & Evans RM. Independent effects of growth hormone releasing factor on growth hormone release and gene transcription. Nature 1985 314 279–281.

8 Kineman RD, Kamegai J & Frohman LA. Growth hormone (GH)- releasing hormone (GHRH) and the GH secretagogue (GHS), L692,585, differentially modulate rat pituitary GHS receptor and GHRH receptor messenger ribonucleic acid levels. Endocrinology 1999 140 3581–3586.

20 Lasko CM, Korytko AI, Wehrenberg WB & Cuttler L. Differential GH-releasing hormone regulation of GHRH receptor mRNA expression in the rat pituitary. American Journal of Physiology 2001 280 E626–631.

2bvajra said:

Swale or Dat, L-argenine has twice been mentioned in this thread but with no elaboration. Functions listed in Wiki look encouraging, but I would like to know if it can serve any useful purpose in an anti-aging regimen.

Click to expand...

Too tired at the moment to start a new topic. I'll be happy to elaborate later.

So you tell me... what do you think Arginine does by looking at the following diagram?

Ah, my little mouse added CJC to his GHRP that he just started back up and he woke up from the best night of sleep he's had in years. He started at 50mcg of cjc and 100 ghrp 3 times per day. Along with his keto diet and he's feeling great. Oh and my mouse is also on a HST workout routine, he's a pretty amazing mouse.

layinwood said:

Ah, my little mouse added CJC to his GHRP that he just started back up and he woke up from the best night of sleep he's had in years. He started at 50mcg of cjc and 100 ghrp 3 times per day. Along with his keto diet and he's feeling great. Oh and my mouse is also on a HST workout routine, he's a pretty amazing mouse.

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Does your mouse have any pre treatment lab scores? Do you plan on giving him/her any post treatment bloodwork?

Wiseguy, I didn't do one before. I really wanted to but getting me for testing was going to take too long and I didn't want to wait.

I'm not sure it would matter but if Dat thinks it would tell us anything(since we'll have nothing to compare it to) then I'll some bloodwork done.