GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Antagonization of Ghrelin Suppresses Muscle Protein Deposition by Altering Gut Microbiota and Serum Amino Acid Composition in a Pig Model.
Yan. Xiaoxi X; Zhang. He H; Lin. Ailian A; Su. Yong Y
Key Findings
- Ghrelin antagonism (using D‑Lys3‑GHRP‑6) reduced growth performance and muscle fiber size in pigs.
- Serum levels of important amino acids (isoleucine, methionine, arginine, tyrosine) dropped with ghrelin blockade.
- Acetate‑producing gut bacteria and colon acetate levels were lower, and mTOR signaling was down‑regulated while autophagy‑related genes were up‑regulated.
Practical Outcomes
- For biohackers, this study suggests that using ghrelin‑blocking compounds could hurt muscle growth and overall performance, likely because they lower key amino acids and suppress the mTOR pathway. It reinforces the idea that ghrelin‑activating peptides (like standard GHRP‑6) may be beneficial for muscle building, while antagonists should be avoided. The gut‑microbiome link also hints that supporting acetate‑producing bacteria could further aid muscle protein synthesis.
Summary
Blocking ghrelin with a special version of GHRP‑6 in pigs made them grow slower, reduced muscle size, lowered key amino acids in the blood, and changed gut bacteria that produce acetate. These changes also turned down the mTOR pathway (which builds muscle) and turned up genes that promote cell cleanup, leading to less muscle protein being deposited.
Abstract
Ghrelin is an appetite-stimulating hormone that can increase food intake and has been reported to prevent muscle loss; however, the mechanism is not yet fully understood. In this study, [D-Lys3]-GHRP-6 (GHRP) was used to investigate the effects of the antagonization of ghrelin on muscle protein deposition, eating patterns and gut microbiota in a pig model. We found that the growth performance and muscle fiber cross-sectional area of pigs treated with GHRP were significantly reduced compared with the control (CON) group. Moreover, the levels of serum isoleucine, methionine, arginine and tyrosine in the GHRP group were lower than that of the CON group. The abundance of acetate-producing bacteria (<i>Oscillospiraceae</i> UCG-005, <i>Parabacteroides</i> and <i>Oscillospiraceae</i> NK4A214 group) and acetate concentration in the colons of pigs treated with GHRP were significantly reduced. In addition, the injection of GHRP down-regulated the mRNA expression of <i>MCT-1</i> and <i>mTOR</i>, and it up-regulated the mRNA expression of <i>HDAC1</i>, <i>FOXO1</i> and <i>Beclin-1</i>. In summary, the antagonization of ghrelin reduced the concentration of important signal molecules (Arg, Met and Ile) that activate the mTOR pathway, concurrently reduce the concentration of HDAC inhibitors (acetate), promote autophagy and finally reduce protein deposition in muscles.
Study Information
pubmed
2022
2022-05-30T00:00:00.000Z
10.3390/biology11060840
14
53