Hormones are chemical messengers that set in motion different processes to keep our bodies working properly. For example, they are involved in regulating our metabolism, immune function, sexual reproduction, and growth. Hormones are made by specialized groups of cells within the body’s glands. The glands—such as the pituitary, thyroid, adrenals, ovaries, and testes—release hormones into the body as needed to stimulate, regulate, and control the function of other tissues and organs involved in biological processes. Most hormones are typically found in very low concentrations in the bloodstream. But a hormone’s concentration will fluctuate depending on the body’s activity or time of day.
We cannot survive without hormones. As children, hormones help us grow up. In our teenage years, they drive puberty. As we get older, some hormone levels naturally decline. But what does that mean? Scientists do not know exactly.
In order to learn more, NIA is investigating how the administration of hormones to older people affects frailty and function. Many of these studies focus on hormones that naturally decline with age, including:
- Human growth hormone
- Estrogen and progesterone (as part of menopausal hormone therapy)
- Dehydroepiandrosterone (DHEA)