Important Terms to Know
Adrenocorticotropic hormone (ACTH) – Polypeptide tropic hormone which is crucial in the hypothalamic-pituitary-adrenal axis. ACTH is produced by the anterior pituitary gland and stimulates the adrenal glands to produce cortisol.
Aldosterone (ALD)- Mineralocorticoid hormone which regulates electrolyte balances by instructing the kidneys to release potassium and retain sodium. It also helps regulate blood pressure.
Adrenal Insufficiency- Condition which results in the lack of cortisol production and can also result in lack of DHEA, aldosterone and disrupt the balance of the immune system, inflammation levels, endocrine hormones, electrolyte homeostasis, sodium and potassium levels and also can impact blood pressure and body temperature regulation. There are many forms of adrenal insufficiency.
Adrenal glands- Walnut shaped glands located on top of each kidney which produce cortisol. catecholamines, DHEA and androgenic steroids. The adrenal gland is comprised of two parts:
1-Adrenal medulla- The inner part of an adrenal gland which controls hormones epinephrine (adrenaline) and norepinephrine (noradrenaline).
2- Adrenal cortex- The outer part of the gland that produces hormones such as cortisol and aldosterone.
Catecholamines- Hormones such as dopamine, epinephrine (adrenaline) and norepinephrine (noradrenaline) that the adrenals produce in response to physical or emotional stress by increasing heart rate and blood pressure.
Cortisol– Glucocorticoid hormone: The body’s stress hormone that is produced by the zona fasciculata. It helps control the body’s use of fats, proteins and carbohydrates; suppresses inflammation, impacts blood pressure and blood sugar. It also controls the body’s sleep/wake cycle and impacts the circadian rhythm.
Circadian rhythm- The body’s natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours. Circadian rhythms can be physical, mental, and behavioral patterns that follow a daily cycle. Cortisol is deeply crucial to circadian rhythm modulation.
CRH (corticotropin-releasing hormone)- A peptide hormone which the signals the pituitary synthesis of ACTH (Adrenocorticotropic hormone).
DHEA– Hormone that aids in the production of androgens and estrogens (male and female sex hormones)
Glucocorticoids- Corticosteroid hormones that bind to glucocorticoid receptors and are part of the feedback mechanism in the immune system which reduces certain aspects of immune function, such as inflammation.
Mineralocorticoids- Corticosteroids that regulate electrolyte balance and fluid balance in the body. In salt wasting forms of adrenal disease, mineralocorticoid replacement is necessary. Medications such as fludrocortisone are used to supplement mineralocorticoid deficiency.
17-Hydroxyprogesterone- Endogenous progestogen steroid hormone related to progesterone which is critical in the biosynthesis of androgens, estrogens, glucocorticoids, and mineralocorticoids.
Diseases/Conditions impacting the Adrenal Glands
Adrenal adenoma- Benign tumor of the adrenal glands, which can lead to overproduction of the adrenal hormones.
Addison’s disease- Autoimmune disease resulting in the destruction of the adrenal glands, rendering them unable to produce proper amounts of cortisol, DHEA & Aldosterone.
Adrenocortical Carcinoma- Cancerous adrenal tumor that tends to develop in the outer layer of the adrenal gland.
Conn’s syndrome- Rare health condition which results in the adrenal glands producing too much aldosterone, also known as primary hyperaldosteronism.
Congenital adrenal hyperplasia (CAH)- Genetic disorder present from birth that impairs the adrenal glands. CAH patients lack the enzymes the adrenal glands use to produce hormones that help regulate metabolism, the immune system, blood pressure and other essential functions.
There are two main types of congenital adrenal hyperplasia—classic and nonclassic. The majority of people diagnosed with this condition do not produce enough 21-hydroxylase, which is the enzyme that helps the adrenal glands make cortisol and aldosterone.
There are also other much rarer forms of CAH such as:
11-Beta hydroxylase deficiency- Form of CAH which can be present in both genders, but in females with the non-classic form of CAH, they may develop excessive body hair growth (hirsutism) and irregular menstruation. Males with this condition do not typically have any signs or symptoms except for small height.
17a-hydroxylase deficiency- Form of CAH which results from a defect in the gene CYP17A1, which encodes for the enzyme 17a-hydroxylase. This causes decreased synthesis of cortisol and sex steroids. Can present with ambiguous genitalia in genetic males and also cause failure of the ovaries to function at puberty in genetic females, resulting in infertility.
3-Beta-hydroxysteroid dehydrogenase deficiency- There are three types of 3BHSD deficiency, the salt-wasting form, non-salt-wasting form, and non-classic form. Males with this condition often present with abnormal external genitalia and suffer from infertility. Females with this deficiency may present with slight genital abnormalities at birth, irregular menstruation, hirsutism, and infertility. 3BHSD deficiency is caused by mutations in the HSD3B2 gene.
Congenital lipoid adrenal hyperplasia- This condition is the most severe form of CAH and may cause early death due to adrenal crisis. In this disorder, the synthesis of all adrenal and gonadal steroid hormones is impaired due to a molecular defect in the steroidogenic acute regulatory protein. Presents in males with ambiguous genitalia.
PORD (P450 oxidoreductase deficiency) – A disorder of steroidogenesis with a broad phenotypic spectrum including cortisol deficiency, altered sex steroid synthesis and disorders of sexual development. Associated cases have been also been linked with a skeletal disorder known as Antley-Bixler syndrome.
Cushing’s disease -When the pituitary gland releases too much adrenocorticotropic hormone (ACTH) resulting in the over production of the hormone, cortisol.
Hypopituitarism- Disorder in which the pituitary gland fails to produce the appropriate amount of hormones, requiring hormone replacement therapy.
May impact one or more of the following hormones:
- Adrenocorticotropic hormone (ACTH) Signals the adrenal gland to release cortisol.
- Antidiuretic hormone (ADH) Regulates water loss by the kidneys.
- Follicle-stimulating hormone (FSH) Regulates sexual function and fertility in males and females.
- Growth hormone (GH) Regulates growth of tissues and bone.
- Luteinizing hormone (LH) Regulates sexual function and fertility in males and females.
- Oxytocin- Signals the uterus to contract during labor and the breasts to release milk.
- Prolactin- Signals female breast development and milk production.
- Thyroid-stimulating hormone (TSH) Signals the thyroid gland to release hormones that affect the body’s metabolism.
Pheochromocytoma- A rare tumor of adrenal gland tissue which results in the release of too much epinephrine and norepinephrine.
Secondary Adrenal Insufficiency- When the pituitary gland does not produce the hormone ATCH
(Adrenocorticotropic hormone) resulting in the lack of cortisol production in the adrenal glands. Can be caused by a variety of facts such as, but not limited to: hypopituitarism, exogenous steroid suppression and pituitary gland tumors.
Sheehan’s syndrome- A condition that affects women during or after childbirth, which causes damage to the pituitary gland causing it to fail to produce enough pituitary hormones, also referred to as postpartum hypopituitarism.
Tertiary Adrenal Insufficiency- When the hypothalamus fails to release CRH (corticotropin-releasing hormone) which stimulates the production of ACTH by the pituitary gland.
Lymphocytic Lypophysitis- Condition in which the pituitary gland becomes damaged by lymphocytes, resulting in pituitary enlargement and impaired function.