GHRP-6 · research summary

Ghrelin is essential for lowering blood pressure during torpor.

Frontiers in endocrinology · 2024. Summary drawn from the study's full text. Each statement is followed by the exact sentence it comes from. This is a research summary, not medical advice.

Study type

Animal study using wild-type and ghrelin gene-deficient mice to investigate blood pressure regulation during torpor induction.
“Male wild-type and ghrelin gene-deficient mice were generated by homologous recombination as previously reported.”

Subjects

Male wild-type (WT) and ghrelin gene-deficient (ghrl-/-) mice.
“Male wild-type (WT) and ghrelin gene-deficient (ghrl-/- ) mice were generated by homologous recombination as previously reported (1).”

Sample size

Five mice per group (n=5) for blood pressure and histological analyses.
“Data are presented as means ± SEM (n = 5); *P < 0.05 versus WT mice.”

Duration

Mice were 10 weeks old at the start of the study, with specific measurements taken at 12 and 14 weeks of age, including a 48-hour fasting period.
“Mice, 10 weeks old, were included in this study and housed five per cage.”

Reported findings

Ghrelin gene deficiency resulted in elevated blood pressure and an abnormal blood pressure rhythm, specifically preventing the reduction of blood pressure during the light phase.
“The ghrelin gene deficiency prevented blood pressure reduction during the light phase, which is the resting phase in nocturnal mice.”
Induction of torpor by fasting did not decrease blood pressure in ghrelin gene-deficient mice, whereas it did in wild-type mice.
“The continuous measurement of blood pressure using a telemetry system showed that induction of torpor by fasting did not decrease blood pressure in ghrelin gene-deficient mice.”
Administration of a ghrelin receptor agonist (GHRP-6) to ghrelin-deficient mice restored blood pressure reduction and normalized sympathetic nerve activity during fasting.
“Furthermore, these features were cancelled by administration of a ghrelin receptor agonist and were comparable to those in wild-type mice.”

Limitations stated by the authors

The study did not investigate the detailed mechanism related to blood pressure rhythm abnormalities associated with ghrelin gene deficiency.
“Although this study did not investigate the detailed mechanism related to blood pressure rhythm abnormalities associated with ghrelin gene deficiency, we were able to clearly demonstrate that ghrelin deficiency causes high blood pressure and abnormal blood pressure rhythms.”

Source: PubMed 39449746 · DOI 10.3389/fendo.2024.1487028 · all study summaries

Reported findings

Ghrelin gene deficiency resulted in elevated blood pressure and an abnormal blood pressure rhythm, specifically preventing the reduction of blood pressure during the light phase.

“The ghrelin gene deficiency prevented blood pressure reduction during the light phase, which is the resting phase in nocturnal mice.”

Induction of torpor by fasting did not decrease blood pressure in ghrelin gene-deficient mice, whereas it did in wild-type mice.

“The continuous measurement of blood pressure using a telemetry system showed that induction of torpor by fasting did not decrease blood pressure in ghrelin gene-deficient mice.”

Administration of a ghrelin receptor agonist (GHRP-6) to ghrelin-deficient mice restored blood pressure reduction and normalized sympathetic nerve activity during fasting.

“Furthermore, these features were cancelled by administration of a ghrelin receptor agonist and were comparable to those in wild-type mice.”

Limitations stated by the authors

The study did not investigate the detailed mechanism related to blood pressure rhythm abnormalities associated with ghrelin gene deficiency.

“Although this study did not investigate the detailed mechanism related to blood pressure rhythm abnormalities associated with ghrelin gene deficiency, we were able to clearly demonstrate that ghrelin deficiency causes high blood pressure and abnormal blood pressure rhythms.”