All hormones regulate one or more of the thousands of metabolic processes occurring every second inside of the human body. Some hormones regulate cellular metabolism. Vitamin D, the sunshine vitamin, is actually a steroid hormone. In the 1850's, scientists first recognized that the thyroid gland produced a substance which regulated metabolism. A decade later, it was noted that the pancreas acted as a gland, secreting a substance that would later be identified as insulin.
Hormones are chemical messengers.
Adrenalin is a hormone. The male equivalent is testosterone. Various hormones have various roles. Prolactin is responsible for regulating milk production while insulin regulates blood sugar levels. There exists a separate group of hormones that regulate growth.