Methods for increasing Sermorelin's Half Life

[Wise Guy]

Hey guys!

This is taken from some really cool discussions me and Datbtru have been having, in particular discussing Sermorelin.

Original post here - http://datbtrue.co.uk/forums/showthread.php?p=9245&posted=1#post9245

We were throwing ideas out back and forth about the direction of GHRT, and specifically about sermorelin.

About how the move away from synthetic GH and into sermorelin came a couple years ago.

And that how, at first, it seemed so promising. But then we couldn't figure out why it didn't work, even if dosed at 300mcg or higher.

But then his work, which opened up the idea that exogenous GHRH analogs like sermorelin cannot boost GHRH because of the presence of somatostatin, and that how he pieced together the idea that if you administer a peptide agent, such as GHRP, this will turn down somatostatin's negative influence and give Sermorelin a green light to boost GHRH.

But then we moved in the direction that the sermorelin that we are using, GRF 1-44, the legal one, the peptide chain is unmodified and

1. Doesn't survive and derades quickly
2. Doesn't have a strong affinity and bind to the receptor tightly.

The solution is obviously a modified form of sermorelin, which has been done. Mod GRF 1-29, which lops off 15 extra amino acids at the end, and is cleaved and modified to be stronger, resist degradation, and bind with a stronger affinity.

Essentially, my ideas was, that it is all fine and dandy that we have GRF 1-29 available as a research chemical, but really......what use is it to us if it isn't legally available as a prescription drug?

What if it never becomes available?

So what can we do with the Sermorelin GRF 1-44 that we have available? Simply kill it (as Dr John noted on the radio show "Sermorelin is Dead" :biggrin:)

Dat countered with some novel and interesting ideas (as he always does)

Apparently, there are methods to help Sermorelin resist degradation. It can be done w/ another prescription drug, or even possibly w/ an OTC herb called Berberine.

[Wise Guy]

Here is his brief overview.

Growth Hormone Releasing Hormone (GHRH) (amplifies the GHRP initiated pulse):

- Growth Hormone Releasing Hormone (GHRH) aka GRF(1-44) (Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2) = half-life "less then 10 minutes", perhaps as low as 5 minutes. - Ref-2


- GRF(1-29) aka Sermorelin (Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2) - the biologically active portion of the 44 amino acid GHRH = half-life "less then 10 minutes", perhaps as low as 5 minutes. - Ref-3

- Longer-lasting analogs of GRF(1-29):

-- replace the 2nd amino acid Alanine w/ D-Alanine only to modify GRF(1-29), D-Ala2 GRF(1-29) (Tyr-DAla-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2) = half-life "closer to 10 minutes" - Ref-4


-- replace the 2nd, 8th, 15th & 27th amino acids & get modified GRF(1-29) or CJC-1295 w/o the DAC (i.e. the part that will bind to albumin & make the half-life days) (Tyr-DAla-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2) = Half-life at least 30 minutes or so - Ref-5

-- CJC-1295 (Tyr-DAla-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-Lys-(Maleimidopropionyl)-NH2) = Half-life measured in days, - Ref-6

In the early studies 25+ years ago the biological activity of Growth Hormone Releasing Hormone (GHRH) was found to reside in what is called the The N-terminus region of the native 40- or 44-amino acid peptide. Both lengths exist. The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) refers to the start of a protein or peptide terminated by an amino acid with a free amine group (-NH2). The convention for writing peptide sequences is to put the N-terminus on the left and write the sequence from N- to C-terminus. When the protein is translated from messenger RNA, it is created from N-terminus to C-terminus.

Wehrenberg WB, Ling N. 1983, In vivo biological potency of rat and human growth hormone-releasing factor and fragments of human growth hormone-releasing factor, Biochem Biophys Res Commun. 115:525-530

Wikipedia

Early human studies demonstrated similar potencies of GHRH-(I-29)-NH2 and GHRH-(1-40) in stimulating GH release. For example, Grossman A, Savage MO, Lytras N, et al. 1984, Responses to analogues of growth hormone-releasing hormone in normal subjects, and in growth-hormone deficient children and young adults, Clin Endocrinol (Oxf). 21:321-329.

"The D-Ala2 analog of GHRH-(l-29)-NH2 has been reported to be approximately 50 times more potent than GHRH-(I-29)-NH2 in stimulating GH release in vivo in rats, but only twice as potent in man. This enhanced potency may reflect increased receptor binding affinity, prolongation of the biological half-life, or both of these components. In rats, there was no significant difference in the clearance of D-Ala GHRH-(1-29) and GHRH-(1-29) after a bolus parenteral injection. This suggested that increases in biological activity were solely due to enhanced receptor affinity."

Quoted from, Incorporation of D-Ala2 in Growth Hormone-Releasing Hormone-( l-29)-NH2 Increases the Half-Life and Decreases Metabolic Clearance in Normal Men, Steven Soule, J Clin Endocrinol Metab 79: 1208-1211, 1994

Which in turn referenced:

Lance VA, Murphy WA, Sueiras-Diaz J, Coy DH. 1984 ,Superactive analogs of growth hormone-releasing factor (l-29) amide, Biochem Biophys Res Commun. 119:265-272.

Barron JL, Coy DH, Millar RP. 1985 Growth hormone responses to growth hormone-releasing hormone (l-29)-NH2 and a D-Ala2 analog in normal men., Peptides. 6:575-577.

Rafferty B, Coy DH, Poole S. 1988, Pharmacokinetic evaluation of superactive analogues of growth hormone-releasing factor (1-29)- amide, Peptides. 9:207-209.

The above quoted Soule study found that:

"The disappearance half-time of the D-Ala2 analog was 6.7 + 0.5, whereas that of GHRH-(l-29))NH, was 4.3 + 1.4 min (P < 0.05). These findings demonstrate that the D-Ala2 substitution contributes to the enhancement of biological activity by reducing metabolic clearance."

[Wise Guy]

Vulnerability #1 (DPP-IV)

Dipeptidyl peptidase-IV (DPP-IV) is the enzyme responsible for mediating cleavage of both GHRH-( l-44)-NH2 and GHRH-( l-29)-NH2 at Ala2- Asp3 in vivo and in vitro. DPP-IV plays a major role in glucose metabolism. It is responsible for the degradation of incretins such as GLP-1. It appears to work as a suppressor in the development of cancer and tumors. Its levels either on the cell surface or in the serum increases in some neoplasms (i.e. benign, pre-malignant or malignant tumors) and decreased in others.

This may be an enzyme that you do not want to manipulate simply to increase the survival of GHRH. Although it may be more beneficial to administer GHRH (non-analog such as Sermorelin) during natural states where DPP-IV is lower.

Oral hypoglycemics called dipeptidyl peptidase-4 inhibitors are available and work by inhibiting the action of this enzyme, thereby prolonging the effect in vivo of those peptides that are vulnerable. Some drugs available for prescription include:

sitagliptin (FDA approved 2006, marketed by Merck & Co. under the trade name Januvia),

vildagliptin (marketed in the EU by Novartis under the trade name Galvus),

There may be no need for a prescription drug as the herb Berberine also inhibits dipeptidyl peptidase-4, which is a primary reason it has anti-hyperglycemic activities (inhibits break down of Glucagon-like peptide-1).

Frohman LA, Downs TR, Heimer E, Felix AM. 1989 Dipeptidylpeptidase IV and trypsin-like enzymatic degradation of human growth hormone-releasing hormone in plasma. J Clin Invest. 83:1533-1544.

Wikipedia

DatBtrue's conclusion from the above is that it may be beneficial to supplement with Berberine when you administer either a native GHRH or the biologically active portion (Sermorelin) OR an analog such as Modified GRF(1-29) which is modified at the 2nd position w/ D-Arg (and thus less but still vulnerable).

[Wise Guy]

What happens after DPP-IV attack?


Well if DPP-IV is successful it results in GHRH-(3-44)- NH2 and for Sermorelin (the biologically active portion of GHRH) GHRH-(3-29)-NH2 These metabolites (missing the cleaved first 2 amino acids) have in vitro bioactivities less than 0.02% that of the native peptide . The D-Ala2 analog, however, has been found to be resistant to DPP-IV cleavage, although from the Bonger study we see that it remains susceptible to trypsin-like degradation between Arg11-Lys12 and Lys12-Va113 residues.

Campbell RM, Lee Y, Rivier J, Heimer EP, Felix AM, Mowles TF 1991, GRF analogs and fragments: correlation between receptor binding, activity and structure, Peptides. 12:569-574.

Bongers J, Lambros T, Ahmad M, Heimer EP. 1992 Kinetics of dipeptidyl peptidase. IV. Proteolysis of growth hormone-releasing factor and analogs, Biochim Biophys Acta 1122:147-153.

Additional amino acid substitution as is found in modified GRF(1-29) reduces degradation but does so not by directly addressing the above vulnerabilities at 11-12 and 12-13 residues but rather indirectly via amino acid substitution at the 2nd, 8th, 15th & 27th positions.

Trypsin-like degradation is an example of a variety of protease known as endopeptidase which breaks down proteins and peptides by attacking an amino-acid bond. This degradation is hugely important to the body in its elimination of the plethora of proteins, fragments and structures which the body as a whole feels serve no remaining purpose. Trypsin predominantly cleaves peptide chains at the carboxyl side (C-Terminus) of the amino acids lysine or arginine, except when either is followed by proline.

The CJC-1295 study which used the 4 maino acid substitutions found in Modified GRF(1-29) found no need to protect against this type of degradation in order to achieve a half-life of 30 minutes plus. However if one were to attempt to reduce this vulnerability either in unmodified GHRHs such as Sermorelin or modified GRF(1-29) they would look into Trypsin inhibitors which reduce the availability of trypsin.

Naturally Trypsin inhibition can be found in ligands from both Lima beans and Soybeans. However note that cooking with these beans destroys the Trypsin inhibitory properties. So a ground extract or whole bean many be effective.

DatBtrue's conclusion is that the concurrent use of Berbine to inhibit DPP-IV degradation and a raw lima bean or soybean extract to inhibit Trypsin degradation may prove useful in enhancing the biological half-life (and thus utility) of unmodifed forms of GHRH (such as Sermorelin) and the analog modifed in 4 places known as modified GRF(1-29).

[keith1958]

Thanks WiseGuy, Sounds like the best way to go is with the Modified GRF(1-29) and GHRP-2 or GHRP-6.

[rick055]

Great info wiseguy, I'm just going to need a slide rule and an excel chart to keep the acronyms straight!!!

[agoraphobe]

wish i knew what any of this shit was, lol.

[Wise Guy]

wish i knew what any of this shit was, lol.

Its simple.

Sermorelin is GRF 1-44. This is the legal one that is available per script via anti aging Dr. Many prescribe this. Dr John did at one time.

It did not work in GHRT because Sermorelin degrades to fast (half life 5 min)

Not strong enough to illicit its price tage ($90 per mg)

Did not release enough GHRH to warrent price.

Dat has explained some novel methods to increase original, available per prescription, sermorelin's half life.

If it holds up in practice who knows.

Sounds cool though :thumbup1: