Ghrelin is secreted mainly in the stomach. It stimulates appetite and increases food intake. Leptin is a hormone, synthesized primarily in fat cells, that has been shown to decrease food intake and increase energy expenditure.
Propane gas does not have an effect on breathing by itself, but displaces oxygen from the air making it hard to breathe. If enough oxygen is displaced, a person could asphyxiate. If the exposure to propane gas is minimal, there are little to no symptoms if inhaled. If oxygen is displaced from the air because of high quantities of propane gas, symptoms that are present are rapid heart rate, clumsiness and fatigue. The longer the exposure occurs, the less oxygen will be present, and symptoms such as vomiting, convulsions and even death can occur.
Hydrogen sulfide gas causes a wide range of health effects. Workers are primarily exposed to hydrogen sulfide by breathing it. The effects depend on how much hydrogen sulfide you breathe and for how long. Exposure to very high concentrations can quickly lead to death.