Intranasal Delivery of a Ghrelin Mimetic Engages the Brain Ghrelin Signaling System in Mice.

Preclinical animal study investigating the effects of intranasal GHSR agonists on food intake, neuronal activation, and growth hormone levels in mice.

“This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.”

Adult male and female C57B6/6J mice.

“All experiments were carried out on adult male C57B6/6J mice (Charles River Laboratories), except for the GH measurements, which were carried out on adult female C57B6/6J mice (Charles River Laboratories) due to a less distributed variance in GH pulse amplitude in females compared to males (41-43).”

Sample sizes ranged from n=5 to n=10 depending on the specific experimental cohort (pilot, meal patterns, Fos mapping, RNAscope, and GH levels).

“In a pilot study, we sought to determine if GHSR agonists, administered via the intranasal route, affect the amount of food eaten in mice (n = 6).”

Intranasal GHRP-6 increased Fos expression in the arcuate nucleus, with activated neurons showing coexpression of Ghsr, Agrp, and Ghrh mRNAs.

“Fos expression in the arcuate nucleus was higher in GHRP-6–treated mice than in saline controls.”

Intranasal GHRP-6 elevated serum growth hormone levels in mice.

“Additionally, intranasal GHRP-6 elevated GH serum levels.”