What Are the Effects of Cortisol?

Cortisol is a hormone normally released during times of stress, to help regulate the body’s stress response. The signal for cortisol secretion begins in the pituitary gland, a gland at the base of the brain. The pituitary secretes a hormone called ACTH, which circulates in the bloodstream and stimulates the production of cortisol in the adrenal glands. Cortisol secreted by the adrenal glands then circulates throughout the body to produce a number of effects.

Increased Blood Sugar

The release of cortisol from the adrenal glands leads to an increase in blood sugar. Cortisol is released when the body is under stress, and the increase in blood sugar provides readily available energy for a possible fight-or-flight response. Cortisol increases blood sugar in two ways, reports Colorado State University. Release of cortisol triggers the generation of glucose within the liver, a process called gluconeogenesis. Cortisol also helps increase blood glucose by inhibiting muscle and fat cells from taking in glucose, thus preserving glucose in the blood. Pathologically high or low levels of cortisol in the blood can have adverse effects on blood sugar regulation within the body.

Decreased Inflammation and Immune Response

Cortisol also has an effect on the immune system: Secretion of cortisol decreases inflammation and suppresses the immune system. Cortisol plays a role in regulating normal inflammation and immune activity in the body, and functions to inhibit factors that promote inflammation, and decreases the activity of white blood cells. Due to its effect on inflammation and the immune system, drugs designed to mimic cortisol can be used to regulate immune function and inflammation in disease. These drugs, called glucocorticoids, are used in the treatment of a number of inflammatory diseases such as asthma. Abnormal levels of cortisol, either due to disease or corticosteroid drug use, can lead to immune suppression that leaves a patient vulnerable to infection.

Decreased Bone Density

Cortisol can also have an effect on bone density. Bone tissue is constantly remodeled within the body, and this remodeling is regulated by two major cell types. Osteoblasts aid in depositing new bone tissue, and osteoclasts break down old bone tissue. The rate at which the cells deposit and break down bone regulates bone density, and underactivity of one cell type leads to changes in bone density.

Cortisol decreases bone density by leading to underactivation of bone-depositing osteoblast cells, reports a 2001 study published in “Bone.” Cortisol was found to decrease osteoblast cell proliferation, so fewer osteoblast cells are available to deposit bone. It also decreases the maturation of osteoblast cells from precursors, further decreasing the number of functional osteoblasts. Without osteoblast activity, more bone tissue is broken down than deposited, and over time this leads to decreased bone density. Patients with sustained high cortisol levels may be at increased risk for osteoporosis.

About this Author

Louise Tremblay recently finished a Master of Science in molecular and cellular biology in Ontario, Canada, following years of cancer research experience. She has experience writing articles and Web content on topics in science, heath and fitness, diet and personal wellness. She is currently pursuing a personal trainer certification.