_____ is a protein secreted by fat cells and, when abundant, causes the brain to increase metabolism and decrease hunger.
Leptin and ghrelin seem to be the big players in regulating appetite, which consequently influences body weight/fat. When we get hungrier, we tend to eat more. When we eat more, obviously, we maintain our body weight or gain that weight back. Both leptin and ghrelin are peripheral signals with central effects. In other words, theyâre secreted in other parts of the body (peripheral) but affect our brain (central). Leptin is secreted primarily in fat cells, as well as the stomach, heart, placenta, and skeletal muscle. Leptin decreases hunger. Ghrelin is secreted primarily in the lining of the stomach.