It is similar to the nervous system in that it plays a vital role in controlling and regulating many of the body's functions.

Most anterior pituitary hormones exhibit a diurnal rhythm of release, which is subject to modification by stimuli influencing the hypothalamus.

GH mobilizes fats, stimulates protein synthesis, and inhibits glucose uptake and metabolism.

The intermediate lobe of the pituitary gland secretes only one enzyme that is melanocyte stimulating hormone.

When thyroid levels are high, there is negative feedback that decreases the amount of Thyroid-stimulating hormone secreted.

The adrenal glands produce a variety of hormones including adrenaline and the steroids aldosterone cortisol and Dehydroepiandrosterone sulfate (DHEA).

Estrogens stimulate the maturation of the female reproductive system and the development of secondary sexual characteristics.

Testosterone promotes maturation of the male reproductive organs, development of secondary sex characteristics such as increased muscle and bone mass, and the growth of body hair.

Examples include the heart (atrial natriuretic peptide); gastrointestinal tract organs (gastrin, secretin, and others); the placenta (hormones of pregnancy—estrogen, progesterone, and others); the kidneys (erythropoietin and renin); the thymus; skin (cholecalciferol); and adipose tissue (leptin and resistin).

[citation needed] The natural decrease in function of the female's ovaries during late middle age results in menopause.

The liver and kidneys are the major organs that degrade hormones; breakdown products are excreted in urine and faeces.

The nervous system, acting through hypothalamic controls, can in certain cases override or modulate hormonal effects.

Endocrine disease is characterized by irregulated hormone release (a productive pituitary adenoma), inappropriate response to signalling (hypothyroidism), lack of a gland (diabetes mellitus type 1, diminished erythropoiesis in chronic kidney failure), or structural enlargement in a critical site such as the thyroid (toxic multinodular goitre).

Hypofunction of endocrine glands can occur as a result of the loss of reserve, hyposecretion, agenesis, atrophy, or active destruction.

Hyperfunction can occur as a result of hypersecretion, loss of suppression, hyperplastic, or neoplastic change, or hyperstimulation.

[citation needed] As the thyroid, and hormones have been implicated in signaling distant tissues to proliferate, for example, the estrogen receptor has been shown to be involved in certain breast cancers.

Dysfunction in the adrenal gland could be due to primary or secondary factors and can result in hypercortisolism or hypocortisolism.

Cushing's disease is characterized by the hypersecretion of the adrenocorticotropic hormone due to a pituitary adenoma that ultimately causes endogenous hypercortisolism by stimulating the adrenal glands.

[8] Graves' disease effects range from excess sweating, fatigue, heat intolerance and high blood pressure to swelling of the eyes that causes redness, puffiness and in rare cases reduced or double vision.

Hyposecretion of insulin results in diabetes mellitus; cardinal signs are polyuria, polydipsia, and polyphagia.