Pharmacokinetic evaluation of superactive analogues of growth hormone-releasing factor (1-29)-amide.
Rafferty. B B; Coy. D H DH; Poole. S S
Key Findings
- D‑amino‑acid substitutions did not extend plasma half‑life beyond the parent peptide (6.2 min).
- Subcutaneous bioavailability of the analogues (4.6‑7.2 %) was similar to that of the original compound (5.1 %).
- Adding conformational restraints increased potency in rats but did not improve resistance to enzymatic breakdown.
Practical Outcomes
- For DIY biohackers, these particular modifications to sermorelin offer no clear advantage in dosing frequency or effectiveness. Stick with the standard peptide formulation, as the analogues do not provide better stability or absorption.
Summary
The study tested modified versions of the growth hormone‑releasing peptide (like sermorelin) to see if they lasted longer in the blood or were absorbed better. The changes did not make a meaningful difference – half‑life and how much got into the bloodstream stayed about the same as the original peptide.
Abstract
D-amino acid-substituted analogues of growth hormone-releasing factor 1-29)-amide with superagonist activities in the rat were examined for increased plasma half-life and resistance to degradation in vivo. After IV injection, half-lives of the analogues were in the range 4.7-7.4 min, none of which was significantly different from that of the parent compound (6.2 min). Following SC injection, 4.6-7.2% of the dose of the analogues reached the circulation compared with 5.1% of the parent compound. Conformational restraints introduced into the N-terminal region of the molecule, which gave enhanced potency, did not alter the susceptibility of the peptide to proteolytic degradation.
Study Information
pubmed
1988
1988-02-29T00:00:00.000Z
10.1016/0196-9781(88)90029-0
15
16