<prompt> Which of the following inhibits appetite by counteracting the effects of neuropeptide Y?OrexinsNeuropeptide YGhrelinLeptin  <response>: Leptin acts on receptors in the hypothalamus of the brain where it inhibits appetite by 1 counteracting the effects of neuropeptide Y a potent feeding stimulant secreted by cells in the gut and in the hypothalamus; 2 counteracting the effects of anandamide another potent feeding stimulant that binds to the same receptors as THC, and 3 promoting the synthesis of a-MSH, an appetite suppressant. Ghrelin is a hormone produced mainly by PD1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger. Neuropeptide Y is a natural substance that acts on the brain to stimulate eating.Leptin reduces the output of NPY from the hypothalamus, a major production center. Orexins hypocretins are neuropeptides primarily localized in the hypothalamus and are implicated in the regulation of a variety of activities, including feeding behavior and energy balance. 