Effect of D-Ala-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2 (KP-102) on GH secretion in urethan-anesthetized rats.
Sawada. H H; Sugihara. H H; Onose. H H; Minami. S S; Shibasaki. T T; Wakabayashi. I I
Key Findings
- KP-102 alone causes a small rise in GH levels in anesthetized rats.
- When combined with exogenous GRF, KP-102 triggers a large increase in plasma GH.
- Blocking somatostatin (using antiserum) makes the KP-102‑plus‑GRF effect even stronger.
- The GH‑boosting effect of KP-102 is reduced if antibodies against GRF are given beforehand.
Practical Outcomes
- For biohackers, the study suggests that a GH‑releasing peptide may need to be paired with a GHRH analog or a somatostatin blocker to see meaningful GH spikes. However, the research is limited to anesthetized rats and uses experimental conditions (e.g., antiserum) that aren’t practical or safe in humans, so it doesn’t provide a ready‑to‑use protocol.
Summary
In rats, a new six‑amino‑acid peptide called KP-102 can boost growth hormone (GH) release, but only when it’s used together with a GH‑releasing factor (GRF) or when the body’s natural GH‑blocking hormone (somatostatin) is blocked. On its own, KP-102 has only a tiny effect.
Abstract
The effect of a newly developed growth hormone (GH)-releasing hexapeptide (KP-102) on GH secretion was studied in urethan-anesthetized adult male rats. Although KP-102 alone exerted a small influence on GH secretion, it produced a large plasma GH response in the presence of exogenous GH-releasing factor (GRF). During the continuous infusion of GRF, the somatotropes became refractory to a large bolus dose of GRF, but KP-102 induced a marked increase of plasma GH. The GH response to KP-102 alone or KP-102 with GRF was significantly augmented when antiserum to somatostatin (ASS) was previously administered. Although KP-102 and GRF acted synergistically on GH secretion in control animals, they acted additively in ASS-administered rats. The KP-102 effect on plasma GH was significantly attenuated in control animals and ASS-administered rats by prior i.v. injection of antiserum to GRF. Taken together, KP-102 stimulates GH secretion dependent on GRF and appears to act synergistically with GRF by antagonizing the SS effect.
Study Information
pubmed
1994
1994-10-21T00:00:00.000Z
10.1016/0167-0115(94)90168-6
14
31