Steroid hormones are created in the gonads and the adrenal cortex. They include testosterone, estrogen, cortisol, aldosterone, and progesterone.

Human growth hormone, oxytocin, and insulin are all peptide hormones, meaning that they are proteins made of amino acids. In contrast, steroid hormones are derived from cholesterol and have distinct ring structures.

There are three primary types of hormones: peptide hormones, steroid hormones, and tyrosine derivative hormones. Of the three, peptide hormones are the only polar hormones, so they cannot pass the cell membrane. As a result, they must attach to a membrane-bound receptor in order to elicit a response in the cell.

Tyrosine derivatives and steroid hormones are smaller, nonpolar molecules. This allows them to pass directly through the membrane, rather than binding to a receptor on the surface. Steroid hormones are derived from cholesterol, but there is no such thing as "cholesterol hormones."

Managing blood sugar levels is primarily the responsibility of the pancreatic hormones glucagon and insulin. Glucagon is responsible for raising blood sugar levels while insulin helps reduce the sugar levels.

Oxytocin is a hormone secreted from the posterior pituitary gland; it induces labor and contractions during childbirth. Thyroxine (also known as thyroid hormone or T4) is secreted from the thyroid and helps regulate metabolism.

The pituitary gland is responsible for a number of peptide hormones, including follicle-stimulating hormone, thyroid-stimulating hormone, and prolactin. Aldosterone, however, is produced in the adrenal cortex and functions to raise blood pressure by preventing fluid loss via urination.