GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Central ghrelin receptor stimulation modulates sex motivation in male rats in a site dependent manner.
Hyland. Lindsay L; Rosenbaum. Stephanie S; Edwards. Alexander A; Palacios. Daniel D; Graham. M Dean MD; Pfaus. James G JG; Woodside. Barbara B; Abizaid. Alfonso A
Key Findings
- Rats with a truncated ghrelin receptor or that are food‑deprived show reduced anticipatory sexual behavior.
- Ghrelin infusion into the VTA does not increase sexual anticipation, but blocking ghrelin there (with D‑Lys‑GHRP‑6) further decreases it in hungry rats.
- Ghrelin infusion into the medial preoptic area (mPOA) lowers sexual anticipation compared to saline or antagonist infusion.
Practical Outcomes
- For biohackers, the study suggests ghrelin signaling influences the balance between sexual drive and food‑seeking behavior, but the effects are highly brain‑region specific and were observed only in rats. There is no clear, safe protocol for using GHRP‑6 or ghrelin modulators to tweak sexual motivation in humans, so the findings are mainly of scientific interest rather than immediate actionable guidance.
Summary
In male rats, activating the ghrelin receptor in different brain spots changes sexual drive: stimulating it in the reward area (VTA) may boost motivation, while stimulating it in the mating area (mPOA) reduces it. Rats lacking a functional ghrelin receptor or those that are food‑restricted show less sexual anticipation. Blocking ghrelin in the VTA further lowers sexual drive in hungry rats, but blocking it in the mPOA has no extra effect.
Abstract
Ghrelin, a hormone produced primarily by the stomach, has been associated with motivational processes that include reward-seeking behaviors. In male laboratory mice, elevation of ghrelin levels enhances some aspects of sexual motivation and behavior, whereas in other experiments with male mice, rats, and other species, ghrelin treatment or food deprivation decreases sexual motivation and/or behavior. The present tested the hypothesis that stimulation of ghrelin receptors in different brain regions have opposite effects on male sexual motivation and behavior. To do this we examined appetitive and consummatory sex behaviors of male rats with a truncated ghrelin receptor (FHH-GHSR<sup>m1/Mcwi</sup>), and that of their WT (FHH) littermates. We also examined the effects of ghrelin or the ghrelin antagonist D-Lys-GHRP6 delivered into the VTA or the MPOA on appetitive and consummatory sex behaviors in male Long Evans rats. Results demonstrate that rats with a truncated ghrelin receptor, or rats that are food deprived, show deficits in anticipatory sex. Furthermore, although ghrelin does not further stimulate sex anticipation in rats when infused into the VTA, intra-VTA infusions of D-Lys-GHRP6 into the VTA further decreases in sex anticipation in food deprived rats. In contrast, ghrelin delivery into the mPOA decreased sex anticipation compared to saline or D-Lys-GHRP6 infused rats. Overall, these data suggest that ghrelin receptor signalling is important for full expression of appetitive sex behaviors. Within the VTA, ghrelin may act to enhance sex motivation, while acting on the mPOA to decrease sex motivation and promote foraging.
Study Information
pubmed
2017
2017-11-08T00:00:00.000Z
10.1016/j.yhbeh.2017.10.012
22
86