The pituitary gland is responsible for secreting key hormones into the bloodstream. These hormones affect other organs and glands in the body. As we age, the pituitary gland naturally changes the production of many of these hormones. Some hormones may increase in production while others may decrease. One  hormone that commonly reduces with age is growth hormone. After the age of 30, there is a progressive decline in growth hormone secretion, and it continues to decrease at a rate of 15% per decade.