When you hear your stomach grumble, it is most likely influenced by the hormone
epinephrine
insulin
ghrelin
cytokines

Ghrelin
ghrelin is a hormone produced by specialized cells that line the stomach and the pancreas.
ghrelin is one of the main hormones to stimulate hunger. ghrelin levels increase before meals and decrease after meals, a mechanism that has its roots in the hypothalamus. if the lateral hypothalamus is removed (as seen in animal studies), feeding becomes less frequent leading to severe weight loss and death. if the ventromedial hypothalamus is removed, feeding increases, leading to weight gain and severe obesity.