Stress and the endocrine system

The response to stress is impossible to separate from the functions of the endocrine system. Indeed, even a small amount of stress can trigger the activation of the hypothalamic-pituitary-adrenal (HPA) axis, which in turn will affect the release of several hormones, activating it for some while inhibiting it for others. Chronic exposure to stress thus induces continuing changes in the secretion of various hormones, with potentially severe consequences:

• The growth axis is inhibited at several levels (growth hormone, insulin-like growth factor, other growth factors), leading to delayed or arrested growth and reduced adult height.

• The thyroid-stimulating hormone is also inhibited during stress, with the consequence of a dysfunction of the thyroid on the long-term, even a hyperthyroidism.

• Stress affects several hormones from the reproductive system, stopping this axis. When chronic, it can induce decreased gonadal functions, thus low hormones levels, amenorrhea and loss of libido.

• Stress-induced decrease in growth hormone and sex steroids, as well as hypogonadism have been associated to the development of osteoporosis.

A broad spectrum of disorders may also be linked to prolonged activation of the HPA axis, such as obsessive-compulsive disorders, panic anxiety, malnutrition, anorexia nervosa, visceral obesity, increased susceptibility of infectious agents, diabetes, etc. There is a large and mutual relationship between stress and the endocrine system and studies are ongoing to try to better understand the mechanisms and the effects.