Adrenaline. Molecular model of part of the hormone adrenaline, or epinephrine (formula C9H13NO3). The atoms are shown as spheres, with the bonds between them as rods. At upper right is a six carbon atom ring. Adrenaline is a hormone produced in the adrenal glands above the kidneys. It is released at times of stress or fear to allow the body to work harder for a short time, leading to a fight or flight" response. It has the effect of increasing the speed and force of the heartbeat, widening the airways to allow the lungs to take in more oxygen, and directing blood to the muscles to allow them to work harder. As a drug, it is used to treat severe asthma and anaphylactic shock."