![zona glomerulosa zona glomerulosa](https://teachmephysiology.com/wp-content/uploads/2017/03/adrenal-histology-768x576.jpg)
The neural crest-derived cells of the medulla secrete catecholamines. The outer mesodermally derived cortex is composed of cells that secrete steroid hormones. Very rare in children and usually inherited (MEN 2b, MEN 2a, NF-1, VHL, familial pheo/para etc).Each of the paired adrenal glands is in fact two glands. (discussed in detail under the ambiguous genitalia section) PheochromocytomaĮtiology: Catecholamine-secreting tumors, arising from chromaffin cells of the adrenal medulla. Treatment: acute phase (IVF, IV hydrocortisone), chronic phase (glucocorticoids and fludrocortisones) Congenital adrenal hyperplasia Symptoms: hypoglycemia, nausea, emesis, fatigue, anorexia, hypotension, hyponatremia, salt craving and hyperkalemia (if aldosterone deficiency), decreased pubic and axillary hair (if adrenal androgen deficiency), hyperpigmentation (due to high MSH).ĭiagnosis: hyponatremia and hyperkalemia, high PRA, low aldosterone, elevated ACTH, failed ACTH stimulation test Central is due to isolated ACTH deficiency or associated with multiple pituitary deficiencies. Primary adrenal insufficiency can be autoimmune, due to congenital adrenal hyperplasia, adrenoleukodystrophy, adrenal hemorrhage etc. Treatment: surgical removal of tumor, supplementary radiotherapy for Cushing disease Adrenal insufficiencyĮtiology: most commonly iatrogenic (treatment with suprpaphysiologic doses of glucocorticoids can result to adrenal suppression) vs primary (adrenal gland is malfunctioning) vs central (pituitary or and hypothalamus are malfunctioning).
#Zona glomerulosa free#
Symptoms: growth stunting, central obesity, facial plethora, buffalo hump, sleep disorders, hypertension, bruising, tinea corporis, and wide striaeĭiagnosis: confirm hypercortisolism with low dose dexamethasone test vs midnight salivary cortisol vs 24-hr urinary free cortisol x3 days, if high cortisol check serum ACTH and refer to endocrinology for more specialized testing and imaging lung or thymic tumor) or excess cortisol secretion by an adrenal tumor. Endogenous is most commonly due to excess pituitary ACTH secretion (Cushing disease or ACTH producing pituitary adenoma) and rarely due to ectopic ACTH production (e.g. Catecholamines are neurotransmitters that regulate various central nervous system functions, but are also hormones that regulate cardiovascular and respiratory function, secretions and muscle contraction.įigure 11: Multiple systemic effects of cortisol Cortisol excess (or Cushing Syndrome)Įtiology: most commonly exogenous (iatrogenic or due to supraphysiologic exposure to glucocorticoids) rarely endogenous.Androgens also serve as precursors of estrogens. Androgens are important for sexual development and reproduction in both males and females.Aldosterone regulates water retention, Na and K balance and body's blood pressure. Aldosterone secretion is under the control of the renin-angiotensin system (not under the control of the brain).Cortisol actions affect almost every body system (Figure 11 below). Cortisol production itself also shuts down the system at the pituitary and hypothalamic levels (negative feedback inhibition). Cortisol secretion is under the control of the hypothalamic CRH and pituitary ACTH.See figure 10 below, where arrows represent enzymes that convert one substrate to another.įigure 10: Main pathways of adrenal steriodogenesis Adrenal steroidogenesis includes three main pathways, leading to cortisol, aldosterone and androgen synthesis, with androgens eventually being aromatized (converted to estrogens). Adrenal glandareas and zones with respective hormones synthesizedĬholesterol (low-density lipoprotein or LDL) is the precursor for adrenal steroidogenesis. The medulla serves as the site of catecholamine, metanephrine and normetanephrine synthesis.įigure 9. The cortex is further divided in 3 zones (zona glomerulosa or site of aldosterone synthesis, zona fasciculata or site of cortisol synthesis and zona reticularis or site of androgen synthesis). The adrenal gland is divided into twodistinct areas, the cortex and the medulla.