Adrenal glands

Primarily stimulated by signals from the kidneys, but also influenced by hypothalamic CRH and pituitary ACTH.

Stimulated mainly by signals from the hypothalamus (CRH) and pituitary (ACTH).

Stimulated by signals from the sympathetic nervous system.

Aldosterone.

Cortisol.

Mineralocorticoids, like aldosterone, regulate salt and water balance in the body.

Glucocorticoids, like cortisol, regulate blood sugar levels, suppress inflammation, and aid in stress response.

The process by which the adrenal cortex produces steroid hormones like cortisol and aldosterone.

The first steroid produced in the adrenal cortex, formed from cholesterol.

The mitochondrion is the cellular organelle where the conversion of cholesterol to pregnenolone takes place.

ACTH (Adrenocorticotropic hormone) directly controls the rate at which cholesterol is converted to pregnenolone.

The conversion of cholesterol to pregnenolone is the slowest step in the synthesis of all adrenocortical hormones, therefore it controls the overall production rate.

The Hypothalamic-Pituitary-Adrenal (HPA) axis is a complex system that regulates the production of cortisol in response to stress and low blood glucose.

Cortisol, a hormone produced by the adrenal glands, plays a crucial role in regulating metabolism, immune function, cardiovascular health, growth, and reproduction.

Cortisol levels increase in response to stress, helping the body cope with challenging situations by mobilizing energy resources.

Cortisol production follows a daily rhythm, peaking in the morning and decreasing in the evening, contributing to our natural sleep-wake cycle.

Low blood glucose levels and various stressors activate the HPA axis, leading to the release of cortisol.

Cortisol helps regulate how the body uses energy from food, affecting blood sugar levels.

Cortisol stimulates the production of enzymes involved in gluconeogenesis, the process of creating glucose from non-carbohydrate sources, like amino acids.

Cortisol acts as an antagonist to insulin. While insulin lowers blood sugar, cortisol raises it by promoting glucose production.

Cortisol decreases the utilization of glucose by peripheral cells, making them less able to use glucose for energy.

Cortisol does not interfere with the brain's glucose utilization. The brain always gets its priority supply.

Cortisol increases the effects of glucagon and epinephrine on glucose metabolism, further boosting blood sugar levels.

Cortisol promotes the breakdown of stored fat (lipolysis) and shifts the body's energy source from glucose to fat.

Cortisol enhances the use of fatty acids (FFAs) as fuel by increasing their oxidation within cells.

Cortisol reduces glucose uptake in fat cells, making it harder for fat to be stored.

Chronic exposure to high levels of cortisol can lead to an increase in abdominal fat (visceral fat), which is linked to obesity and health risks.

Cortisol can cause a shift in fat storage from peripheral areas to visceral areas (around internal organs).

Reduces the body's immune response by decreasing the production of inflammatory chemicals (prostaglandins, leukotrienes, histamine) and suppressing antibody formation, resulting in reduced inflammation.

They down-regulate pro-inflammatory factors, which promote inflammation, while up-regulating anti-inflammatory factors, which suppress inflammation. This leads to an overall reduction in inflammation.

Immune suppressants decrease phagocytosis by immune cells, which are responsible for engulfing and destroying harmful invaders.

Immune suppressants suppress the production of antibodies, which are protein molecules produced by the immune system to fight off specific infections.

Immune suppressants effectively inhibit inflammation by decreasing the production of inflammatory chemicals, suppressing antibody formation, and reducing the activity of immune cells.

Cortisol helps maintain blood pressure by increasing the sensitivity of blood vessels to vasoconstrictors, reducing the release of vasodilators, and boosting the effects of catecholamines.

Cortisol can reduce reproductive success by interfering with various processes in the reproductive system.

Cortisol can inhibit growth through various mechanisms.

Cortisol inhibits functions not essential for survival when the body is under stress.

Cortisol plays a crucial role in regulating metabolism, immunity, cardiovascular health, growth, and reproduction, and is essential for responding to stress.

Androgens are hormones that bind to male sex hormone receptors, triggering specific biological responses in the body.

Dehydroepiandrosterone (DHEA) is converted into DHEA-sulfate by the enzyme sulfotransferase, and into androstenedione by the enzyme 3β−HSD.

Androstenedione, produced from DHEA, is released into the bloodstream and taken up by the testes and ovaries to produce testosterone and estrogens.

The testes convert androstenedione into testosterone, the primary male sex hormone.

The ovaries convert androstenedione into estrogens, the primary female sex hormones.

Neuroendocrine cells found in the adrenal medulla and sympathetic paraganglia. They are modified post-ganglionic sympathetic neurons that lack dendrites and axons. They produce and release catecholamines like adrenaline (epinephrine) and noradrenaline (norepinephrine).

According to the traditional view, acetylcholine (ACh) released from pre-ganglionic sympathetic neurons binds to nicotinic receptors on chromaffin cells, stimulating them to release catecholamines.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide found to be essential for stress-induced catecholamine secretion. It plays a key role in the body's response to stress.

In unstressed animals, acetylcholine (ACh) is the main neurotransmitter activating chromaffin cells. However, during stress, there's a shift to noncholinergic neurotransmission, with PACAP becoming the primary neurotransmitter.

Stress leads to an increased electrical discharge in the splanchnic nerve, stimulating chromaffin cells. The increased discharge also results in more nerve fibers innervating the adrenal medulla, leading to an amplified response.

An enzyme crucial in the synthesis of essential neurotransmitters like dopamine, norepinephrine, and epinephrine. It catalyzes the conversion of tyrosine to DOPA, the first step in the process.

Short for 3,4-dihydroxyphenylalanine, DOPA is an amino acid produced from tyrosine. It is a precursor to dopamine, a vital neurotransmitter involved in mood, reward, and movement.

A group of neurotransmitters, including dopamine, norepinephrine, and epinephrine, that play a vital role in the body's 'fight-or-flight' response, regulating heart rate, blood pressure, and alertness.

Both are powerful hormones, part of the catecholamine family. Epinephrine (adrenaline) is released in response to stress, increasing heart rate and blood pressure. Norepinephrine, also called noradrenaline, plays a role in regulating mood, sleep, and arousal.

The synthesis of catecholamines begins with the conversion of the amino acid tyrosine into DOPA by the enzyme tyrosine hydroxylase.

A condition caused by a deficiency of cortisol and/or aldosterone, primarily affecting the adrenal glands (primary) or the pituitary gland (secondary).

A type of Addison's Disease where the adrenal gland is malfunctioning, resulting in increased ACTH levels due to lack of negative feedback and reduced response to exogenous ACTH.

A type of Addison's Disease where the pituitary gland is malfunctioning, leading to decreased ACTH levels and potential reduced response to exogenous ACTH.

ACTH administered from an external source, used to test the adrenal gland's responsiveness.

ACTH produced naturally within the body.