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.
Although your lungs can hold about four minutes worth of oxygen, your body will likely prompt you to gasp for air near the one-minute mark. Researchers call this inhale moment the breakpoint.. The breakpoint likely occurs when your diaphragm signals your body to take a breath.