A recent study examined the effects the growth hormone agonist, ghrelin, had on Guinea Pig antral and pyloric smooth muscle tissue. Ghrelin is partially responsible for stimulating hunger along with increasing motility & digestive juices.
The test involved some semi-creepy & science fiction sounding stuff. Guinea Pig tissue was suspended within a “tissue bath”, In Vitro(outside of body). The tissue was stimulated via electrical field stimulation at various frequencies(2,4,8,16Hz) & the response to the stimulation was measured. Once baseline values were set the researchers applied ghrelin to the tissue. The ghrelin was found to increase the contractile effects of the electrical field stimulation. The effects were repeatable with multiple administrations of ghrelin showing similar results.Various dosages were tested, but increasing the dosage was not found to increase the effect.
Another recent study was done using rats who were given “Urocortin 1” which caused delayed stomach emptying via reduction of circulating ghrelin. The rats stomach emptying was restored when they were given supplemental ghrelin.
Both studies suggest that ghrelin has a powerful effect on regulating our hunger & digestive motility and they both point towards ghrelin possibly being useful for treating motility disorders like Gastroparesis.
If you want to learn more about ghrelin there is a great overview of past studies by Hanaa S. Sallam and Jiande D. Z. Chen – The Prokinetic Face of Ghrelin