GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Ghrelin modulates gene and protein expression of digestive enzymes in the intestine and hepatopancreas of goldfish (Carassius auratus) via the GHS-R1a: Possible roles of PLC/PKC and AC/PKA intracellular signaling pathways.
Blanco. Ayelén Melisa AM; Bertucci. Juan Ignacio JI; Sánchez-Bretaño. Aída A; Delgado. María Jesús MJ; Valenciano. Ana Isabel AI; Unniappan. Suraj S
Key Findings
- Ghrelin and its receptor GHS‑R1a are located together with key digestive enzymes in fish intestine and hepatopancreas.
- Adding ghrelin to fish tissue cultures increases the expression of several digestive enzymes in a dose‑ and time‑dependent way.
- Blocking the ghrelin receptor with [D‑Lys3]‑GHRP‑6 stops the ghrelin‑induced enzyme boost, and inhibitors of PLC/PKC or AC/PKA pathways reduce many of these effects.
Practical Outcomes
- For biohackers, the data hint that activating ghrelin signaling (e.g., with ghrelin agonists like GHRP‑6) might enhance digestive enzyme activity, potentially improving nutrient absorption. However, the work was done in goldfish, not humans, so the relevance to human digestion is uncertain. Until human studies confirm similar effects, using ghrelin‑related peptides for digestive benefits should be approached cautiously.
Summary
The study shows that in goldfish, the hormone ghrelin works with its receptor (GHS‑R1a) to boost the production of digestive enzymes in the gut and liver. When the fish tissues were treated with ghrelin, enzyme levels went up, and this effect was stopped by a blocker called [D‑Lys3]‑GHRP‑6, which blocks the ghrelin receptor. The researchers also found that the signaling pathways PLC/PKC and AC/PKA are part of how ghrelin does this.
Abstract
Ghrelin, a multifunctional gut-brain hormone, is involved in the regulation of gastric functions in mammals. This study aimed to determine whether ghrelin modulates digestive enzymes in goldfish (Carassius auratus). Immunofluorescence microscopy found colocalization of ghrelin, GHS-R1a and the digestive enzymes sucrase-isomaltase, aminopeptidase A, trypsin and lipoprotein lipase in intestinal and hepatopancreatic cells. In vitro ghrelin treatment in intestinal and hepatopancreas explant culture led to a concentration- and time-dependent modulation (mainly stimulatory) of most of the digestive enzymes tested. The ghrelin-induced upregulations of digestive enzyme expression were all abolished by preincubation with the GHS-R1a ghrelin receptor antagonist [D-Lys3]-GHRP-6, and most of them by the phospholipase C inhibitor U73122 or the protein kinase A inhibitor H89. This indicates that ghrelin effects on digestive enzymes are mediated by GHS-R1a, partly by triggering the PLC/PKC and AC/PKA intracellular signaling pathways. These data suggest a role for ghrelin on digestive processes in fish.
Study Information
pubmed
2016
2016-12-29T00:00:00.000Z
10.1016/j.mce.2016.12.027
26
69