Growth hormone in sports which the anterior pituitary gland produces excess growth hormone. Human growth hormone occurs naturally in the human body. Use of exogenous human growth hormone (HGH), via injection, was originally for medical purposes until athletes began abusing HGH with the goal of increasing their abilities. Before recombinant human growth hormone (rHGH) was developed in 1981, HGH was only available from cadavers. The arrival of rHGH combined with other peptide hormone advancements has increased the availability of HGH on both the legitimate and black markets. The first description of the use of GM as a doping agent was Dan Duchaine’s “Underground Steroid
Effect of spaceflight on the human body enough oxygen to the brain without the astronaut's fainting or becoming dizzy. "Under the effects of the earth's gravity, blood and other body fluids are pulled towards the lower body. When gravity is taken away or reduced during space exploration, the blood tends to collect in the upper body instead, resulting in facial edema and other unwelcome side effects. Upon return to earth, the blood begins to pool in the lower extremities again, resulting in orthostatic hypotension." In 2013 NASA published a study that found changes to the eyes and eyesight of monkeys with spaceflights longer than 6 months. Noted