Physiology: Adrenal Glands
What are the chronic effects of ACTH ?
(1) an increase in growth and cell proliferation in the zona fasciculata and reticularis (2) the increased synthesis of steroidogenic enzymes, LDL receptors and other proteins
Role of ADH and Aldosterone during stress
- Retention of sodium and water: -- Protects ECF and blood volume. -- Important during heavy sweating and in case of blood loss.
What are glucocorticoids used for?
-Autoimmune diseases -Allergic reactions
What are the negative feedback effects of cortisol?
1) the hypothalamus decreases formation of CRH and (2) the anterior pituitary gland to decrease formation of ACTH Both help regulate the plasma concentration of cortisol. Not too much cortisol, by regulating ACTH
What is Cushing's syndrome?
1. (hypercortisolism) 2. Caused from excess pituitary gland ACTH production 3. Weight gain 4. Buffalo Hump- fat accumulation in the upper back 5. Moon face- fat accumulation in the face
What is the normal concentration of cortisol?
12 μg/100 ml
What is the normal concentration of aldosterone?
6 ng /100 ml
Where is the hormone epinephrine produced naturally in the body? Adrenal Medulla Zona Glomerulosa Zona Fasciculata Zona Reticularis
Adrenal Medulla
What are the side effects of treatment of glucocorticoid?
Adrenal effects= Atrophy of adrenal cortex Muscle effects= Muscle atrophy- Bone effects =(inhibits osteoblasts)-Osteoporosis and osteopenia Skin effects=Blunted epidermal cell division in skin, Decreased collagen, inhibition of fibroblasts Net effects, thin skin, easy bruising, striae Immune effects= lowered resistance to infection
What are the effects of long term suppression of ACTH release ?
Adrenal gland atrophy
Cortisol role in lipolysis ?
After hours after a fast , its an increase in circulating levels of fatty acids and glycerol , meaning its a decline in insulin which will inhibit lipolysis and suppress HSL and increase in basal and hormone stimulated lipolysis Cortisol principal action involves inducing the synthesis of hormone sensitive lipase and other proteins necessary to support fat mobilization and enhance epinephrine- andGH-stimulated lipolysis
Selective destruction of the zona glomerulosa of the adrenal cortex would produce a deficiency of which hormone? Aldosterone Androstenedione Cortisol Dehydroepiandrosterone Testosterone
Aldosterone Aldosterone is produced in the zona glomerulosa of the adrenal cortex because that layer contains the enzyme for conversion of corticosterone to aldosterone (aldosterone synthase). Cortisol is produced in the zona fasciculata. Androstenedione and dehydroepiandrosterone are produced in the zona reticularis. Testosterone is produced in the testes, not in the adrenal cortex.
What is the relationship between elevated blood glucose concentration and Adrenal Diabetes?
Both the increased gluconeogenesis and moderate reduction in glucose utilization by the cells cause the blood glucose concentrations to rise. The rise in blood glucose in turn stimulates insulin secretion High levels of glucocorticoid reduce the sensitivity of many tissue to the stimulatory effects of insulin on glucose uptake and utilization So much glucose can lead to adrenal diabetes
What are the circadian rhythm of glucoroticoid secretion ?
CRF, ACTH , and cortisol release are high early morning and low in the evening high of about 20 μg/dl an hour before arising in the morning -a low of about 5 μg/dl around midnight
What is the MOA for alpha -adrenergic receptors?
Ca2+ channels to open release of Ca2+ from endoplasmic reticulum by activating phospholipase Cenzyme open K + channels decrease cAMP synthesis (DIFFERENTIAL FROM beta-adrenergic receptors) or stimulate the synthesis of eicosanoid molecules, such as prostaglandins a1- ↑ IP3, Ca2+, α2 - ↓ cAMP Greater affinity for NE >E, so not important in repsonses to acute stess
What is the regulation of cortisol?
Controlled by secretion of ACTH (Adrenocorticotropic Hormone from the Pituitary Gland) ACTH is controlled by Corticotropin-Releasing Factor (CRF) from the Hypothalamus
What are the actions of ACTH and its releasing ability?
Corticotropes release ACTH in secretory pulses throughout the day (7 to 13 pulses/day) in conjunction with the release of cortisol from the adrenal cortex in a puslatile fashion increase the hydrolysis of stored cholesterol esters, an increase in the synthesis of the StAR protein which facilitates the entry of cholesterol into the mitochondria and an increase in steroid hormone synthesis increases blood flow to the adrenal cortex
What hormone is important in resisting stress and inflammation?
Cortisol , physcial or neurogenic There will be an immediate and marked increase in ACTH secretion by the anterior pituitary gland-followed within minutes by greatly increased adreno cortical secretion of cortisol Ex: -Trauma -Infection -Intense heat or cold -Injection of norepinephrine and other sympathomimetic drugs -Surgery -Debilitating diseases
How is gluconeogenesis stimualted via cortisol ?
Cortisol increases the enzymes required to convert amino acids into glucose in liver cells Cortisol mobilization of amino acids from extrahepatic tissues to promote formation of gluocse Cortisol antagonizes insulin's effects to inhibit gluconeogenesis in the liver. Overall: Increase glucose production Increase tin Glycogen stroage in Liver Cells Increased Gluconeogensis that affects epinephrine and glucagon, to mobilizeglucose in times of need, such as between meals.
What is the importance of adrenal blood circulation?
Cortisol is secreted into blood in the middle &inner zones of cortex, then flows to medulla Increased secretion of cortisol stimulates conversion of norepinephrine to epinephrine Epinephrine rises to > 80% of total catecholamines Epinephrine's effects are stronger than norepinephrine's effects during an acute stress response
Which of the following causes increased aldosterone secretion? Decreased blood volume Administration of an inhibitor of angiotensin-converting enzyme (ACE) Hyperosmolarity Hypokalemia
Decreased blood volume Decreased blood volume stimulates the secretion of renin (because of decreased renal perfusion pressure) and initiates the renin-angiotensin- aldosterone cascade. Angiotensin-converting enzyme (ACE) inhibitors block the cascade by decreasing the production of angiotensin II. Hyperosmolarity stimulates antidiuretic hormone (ADH) (not aldosterone) secretion. Hyperkalemia, not hypokalemia, directly stimulates aldosterone secretion by the adrenal cortex.
What is the relationship between Aldosterone deficiency and how it causes hyperkalemia and Cardiac Toxicity ?
Deficient Aldosterone= K+ rises above normal (60%-100%) , can cause serious cardiac toxicity This includes weakness of the heart contraction , arrhythmia, and lead to heart failure
Protein-bound steroid hormones _____have biologic activity,
Don't
Describe Catecholamine receptors?
E=NE
What are the characteristics of Beta 1 Receptors?
E>NE
The adrenal medulla is composed of modified sympathetic ganglion cells, which is nervous in nature and secretes hormone upon stimulation. Which of these hormones are secreted? Aldosterone Cortisol Epinephrine Testosterone Insulin
Epinephrine
What is the regulation of epinephrine and norepinephrine?
Epinephrine and norepeinehrine combine with α-adrenergic or β-adrenergic receptors , which are membrane bound receptors that function through G protein mechanism that are fast compared to slow steroid hormone action
Which of the following would most likely occur if plasma aldosterone levels were low? Hyperkalemia Hypokalemia Hypernatremia Hypertension
Hyperkalemia Aldosterone increases the Na+K+ ATPase in the basolateral membrane of the principal cells and increases ENaC channels in the luminal side. This creates a driving force for Na+ reabsorption and K+ excretion leading to hypokalemia. When aldosterone is low, K+ excretion is attenuated, leading to hyperkalemia.
What is the relationship of excess aldosterone and muscle weakness?
Hypokalemia loss of K+ into the urine Stimulation transport of K+ from the extracellular fluid into most cells of the body When K+ falls below about on-half normal , severe muscle weakness develops
What causes the secretion of aldosterone?
INCREASED K+ ion concentration INCREASED angiotensin ll concentration ( INCREASEd sodium ion concentration in the extracellular fluid
Which condition contributes to "sodium or aldosterone escape" in persons with Conn's syndrome (hyperaldosteronism)? Decreased plasma levels of atrial natriuretic peptide Increased plasma levels of angiotensin II Decreased sodium reabsorption in the collecting tubules Increased arterial pressure
Increased arterial pressure Under chronic conditions, the effects of high plasma levels of aldosterone to promote sodium reabsorption in the collecting tubules are sustained. However, persistent sodium retention does not occur because of concomitant changes that promote sodium excretion. These changes include increased arterial pressure, increased plasma levels of atrial natriuretic peptide, and decreased plasma angiotensin II concentration.
Cortisone is administered to a 30-year-old woman for the treatment of an autoimmune disease. Which of the following is most likely to occur? Increased ACTH secretion Increased cortisol secretion Increased insulin secretion Increased muscle mass Hypoglycemia between meals
Increased insulin secretion Steroids with potent glucocorticoid activity tend to increase plasma glucose concentration. As a result, insulin secretion is stimulated. Increased glucocorticoid activity also diminishes muscle protein. Because of feedback, cortisone administration leads to a decrease in adrenocorticotropic hormone secretion and therefore a decrease in plasma cortisol concentration.
What regulates Aldosterone Secretion ?
Increased potassium ion Concentration Increased angiotension ll levels due to low sodium , volume depletion or low blood pressure Will cause renal sodium and water retention , helping restore extracelllular fluid volume and blood pressure toward normal
A 40-year-old woman consumes a high-potassium diet for several weeks. Which hormonal change is most likely to occur? Increased secretion of DHEA Increased secretion of cortisol Increased secretion of aldosterone Increased secretion of ACTH Decreased secretion of CRH
Increased secretion of aldosterone Potassium is a potent stimulus for aldosterone secretion, as is angiotensin II. Therefore, a patient consuming a high-potassium diet would exhibit high circulating levels of aldosterone.
Fight or Flight response
Increased secretion of cortisol, ADH, aldosterone, the pancreatic hormone glucagon & growth hormone • All coordinated by hypothalamus through posterior & anterior pituitary, and through sympathetic nervous system +Look at picture
What are the permissive effects (making sure the cell has the full capacity to fully respond when a process is activated) of cortisol ?
Induce expression of glycogen synthase so that more glycogen can be formed in response to insulin stimulation Epinephrine and glucagon mobilization of stored glycogen , cortisol induces glycogenolysis , to ensure more substrate (glycogen) for glucagon and epinephrine to mobilize Cortisol itself does not induce glycogenolysis
What is the role of macula densa cells and and Juxtaglemerular cells when it comes to the Juxtagomerular Apparatus
Macula densa cells contain chemoreceptors and detect sodium levels Juxtaglomerular cells have barareceptors and detect stretch in vascular wall (blood pressure)
A 46-year-old woman has hirsutism, hyperglycemia, obesity, muscle wasting, and increased circulating levels of adrenocorticotropic hormone (ACTH). The most likely cause of her symptoms is Primary adrenocortical insufficiency (Addison disease) Pheochromocytoma Primary overproduction of ACTH (Cushing disease) Treatment with exogenous glucocorticoids Hypophysectomy
Primary overproduction of ACTH (Cushing disease) This woman has the classic symptoms of a primary elevation of adrenocorticotropic hormone (ACTH) (Cushing disease). Elevation of ACTH stimulates overproduction of glucocorticoids and androgens. Treatment with pharmacologic doses of glucocorticoids would produce similar symptoms, except that circulating levels of ACTH would be low because of negative feedback suppression at both the hypothalamic (corticotropin-releasing hormone [CRH]) and anterior pituitary (ACTH) levels. Addison disease is caused by primary adrenocortical insufficiency. Although a patient with Addison disease would have increased levels of ACTH (because of the loss of negative feedback inhibition), the symptoms would be of glucocorticoid deficit, not excess. Hypophysectomy would remove the source of ACTH. A pheochromocytoma is a tumor of the adrenal medulla that secretes catecholamines.
Cortisol and GH are most dissimilar in their metabolic effects on which of the following? Protein synthesis in muscle Glucose uptake in peripheral tissues Plasma glucose concentration Mobilization of triglycerides
Protein synthesis in muscle GH and cortisol have opposite effects on protein synthesis in muscle. GH is anabolic and promotes protein synthesis in most cells of the body, whereas cortisol decreases protein synthesis in extrahepatic cells, including muscle. Both hormones impair glucose uptake in peripheral tissues and therefore tend to increase plasma glucose concentration. Both hormones also mobilize triglycerides from fat stores.
What are the permissive efffects of cortisol on the sympathetic system?
Regualtes Blood pressure Increases the expression of adrenergic receptors Increased levels can cause high blood pressure and are linked with Cushing syndrome
Whats the difference between aldosterone on renal tubules than on sweat glands, salivary glands and the intestines ?
Same effect Sweat glands= effect is in important to conserve body salt in hot environments Enhances sodium absorption by the intestines, especially in the colon, whichprevents loss of sodium in the stools
What is the role of the Adrenal medulla?
Secrete epinephrine from chromaffin cells (80%) m which is the only source for epinephrine and secrete norepinephrine (20%) , norepinephrine can also be secreted by nerve terminals Secretion of these two hormones are important for acute response to stress by duce an array of adaptive responsesby binding to and activating an assortment of adrenergic receptor subtypes.
What are the functions of Aldosterone ?
Secreted from the Zona Glemerulosa cells fo the adrenal cortex Regulates sodium reabsorption and secretion of potassium and hydrogen ions by the renal tubules , mainly on the principal cells of the cortical collecting tube Regulates sodium reabsorption in sweat glands , salivary glands, and intestine Help regulate body fluid volume and blood pressure
Anti-inflammatory effect of High levels of Cortisol ?
Stabalizes lysosomal membrane Decreases permeability of the capillaries Decreased migration of WBCs Reduce B and T cells levels in the blood Decrease production of lymphocytes Negative effect in Mast Cells Reduces release of interlukin-1 Blocks NFKB Suppresses the effects of COX2 , PLA2 , Lipoxygenase
What is the the fight or flight response to acute stress?
Sudden sympathetic outflow from the CNS Prepares body for sudden intense activity during physical danger Occurs also with mental or emotional stress
How does exogenous glucocorticoids inhibit CRH , ACTH , and Endogenous Cortisol Secretion ?
Synthetic gluocorticoids Enhanced activity of synthetic glucocorticoids is due to their:-increased affinity for the glucocorticoid receptor-delayed plasma clearance Synthetic glucocorticoids Examples: Dexamethasone & Prednisone
How does excess aldosterone causes metabolic alkalosis?
The function of aldosterone will cause potassium o be secreted in to the tubules in exchange for sodium reabsorption in the principal cells of the renal collecting tubules. causes secretion of hydrogen ions in exchange for potassium in the intercalated cells of the cortical collecting tubules Decrease in the hydrogen ion concentration in the extracellilar fluid
What is the Aldosterone Escape?
When sodium is reabsorbed there is also a simultaneous osmotic absorption of equivalent amount of water Small increases in extracellular fluid sodium concentration will increase the secretion of antidiuretic hormone, which enhances water reabsorption by the distal and collecting tubules of the kidneys. Therefore, the extracellular fluid volume increases almost as much as the retained sodium, but without much change in sodium concentration. Increased plasma osmolarity will also stimulate thirst and increased water intake, if water is available. +the picture attach
Increased adrenocorticotropic hormone (ACTH) secretion would be expected in patients With chronic adrenocortical insufficiency (Addison disease) With primary adrenocortical hyperplasia Who are receiving glucocorticoid for immunosuppression after a renal transplant With elevated levels of angiotensin II
With chronic adrenocortical insufficiency (Addison disease) Addison disease is caused by primary adrenocortical insufficiency. The resulting decrease in cortisol production causes a decrease in negative feedback inhibition on the hypothalamus and the anterior pituitary. Both of these conditions will result in increased adrenocorticotropic hormone (ACTH) secretion. Patients who have adrenocortical hyperplasia or who are receiving exogenous glucocorticoid will have an increase in the negative feedback inhibition of ACTH secretion
What are the efffects of excess cortisol secretion ?
a type of obesity, which exhibit the following characteristic: -excess deposition of fat in the central and head regions of the body -buffalo-like torso -rounded "moon face.
What are the effects of excessive ACTH production ?
adrenal gland to hypertophy
What is the MOA of beta-adrenergic receptors?
all increase cAMP synthesis (Differential from alpha adrenergic receptors) β1 - ↑ cAMP β2 - ↑ cAMP β3 - ↑ cAMP
How does the hypokalemia biologically cause muscle weakness?
alteration of the electrical excitability of the nerve and muscle fiber membranes, which prevents transmission of normal action potentials Hypokalemia will cause Increased in K+ Diffusion out of the cell to cause hyperpolarization and decrease the excitability
What are steroids bound to, and how does that help me lipid soluble steroid hormone?
binds to a binding protein to allow steroid hormones to be tranported through the plasma at concentrations much greater than that predicted by their limited solubility in aqueous solutions Serve as a plasma reservoir to protect steroid hormones from being metabolized and be excreted by the kidneys Increase steroid hormones half lives
What is pheochromocytoma?
catecholamine-producing tumors of chromaffin cells of the adrenal medulla (90%) orextra-adrenal ganglia. Hypertension is the most common clinical feature. Other symptoms which may occurinclude tachycardia, tremors, sweating, anxiety and headache. Symptoms are often intermittent. Patients withthis condition may also experience weight loss, an increased metabolic rate and glucose intolerance
What is the the relationship between cortisol and decreased ultilzation in cells?
causes a moderate decrease in glucose utilization by most cells in the body (except the brain)
What are the three steroid hormone binding proteins?
corticosteroid-binding globulin (transcortin, which binds cortisol and aldosterone)• sex hormone-binding globulin (binds estrogens and androgens)• vitamin D-binding globulin
How is ACTH regulated?
corticotropin-releasing hormone (CRH) via their release from the hypothalmis neurons through secretory pulses into the capillary bed of the median eminence. Will bind to GPCR membrane receptors that are coupled to adenylyl cyclase (AC) by stimulatory G proteins (Gs) to stimulate AC and cause cAMP rises to activate PKA to phsophorylate P-proteins that stimulate ACTH secretion and the expression of the proopiomelanocortin (POMC) gene.
What is MOA of aldosterone deficiency causing metabolic acidosis?
decreased secretion of hydrogen ions in exchange for potassium in the intercalated cells of the cortical collecting tubules. This increases the hydrogen ion concentration in the extracellular fluid
The unbound or free fraction of a given steroid hormone is in _____ with the fraction that is bound to binding proteins.
equilibrium The free fraction can readily bind to receptors in target tissues and induce a physiological response
What is the affect of conjugated free steroid hormones ?
facilitates the clearance of inactivated steroid hormones by increasing their solubility in water and decreasing their affinity for binding proteins. Thus they are excreted by the kidneys
Only the_______ can diffuse across cell membrane and act on their nuclear receptors.
free hormones
What is the MOA of Steroid Hormone Inactivation ?
free steroid hormones are susceptibel to metabolism and excretion , they are degraded and coverted to inactivae metabolites due to humans not being able to break down the steroid nucleus This process takes place in the liver and will lead to conjugated glucuronic acid and sulfate as the steroid hormone inactivation
What other hormones are effective due to the absence of cortisol?
glycogen synthase expression to support epinephrine- and/or glucagon-stimulated glycogenolysis hormone-sensitive lipase expression to support epinephrine-stimulated lipolysis epinephrine and norepinephrine to adequately constrict blood vessels hemorrhage and severe dehydration are more likely to result in shock
What is also secondary to the exposed to high levels of aldosterone?
hypertension , will last longer with exposure
How does aldosterone affect plasma sodium concentration?
hyponatremia , due to reduced renal sodium reabsorption and increased sodium excretion The renal sodium wasting causes reductions in extracellular fluid volume , reduction in arterial pressure , reduction in cardiac output , stimulation secretion of Antidiuretic hormone (ADH)
What are the regulators of cortisol secretion ?
hypothalamic hormone,Corticotropin Releasing Hormone (CRH), pituitary hormone Adrenocorticotropin (ACTH), in the hypothalamus-pituitary-adrenal axis.
What is the effect of stress?
hypothalamus helps prepare the body for "fight or flight" by triggering sympathetic impulses to various organs.It also stimulates epinephrine release, intensifying the sympathetic responses The hypothalamus also stimulates the adrenal cortex to release cortisol, which promotes longer-term responses that resist the effects of stress
What contributes to the hyponatremia due to aldosterone deficiency , hypovolemia, and hypotension
increased levels of ADH Increased in thirst Increased water intake
What can slightly decreases aldosterone secretion?
increased sodium ion concentration
What are the renal effects of aldosterone?
increasing the expression level of the Na+-K+ ATPase pump on the basolateral side of the cortical collecting tubule membrane to increase sodium reabsorption and potassium secretion increases the sodiumpermeability of the luminal side of themembrane by stimulating the insertion ofepithelial sodium channels.
What is the adrenal Medulla?
inner portion of the adrenal gland that is known as a sympathetic ganglion containing modified postganglionic cells (chromaffin cells) that secrete catecholamines directly into the blood stream Chromaffin cells are innervated by cholinergic preganglionic fibers The adrenal medulla is perfused byarterial blood from medullary arterioles and by blood from the cortical sinusoids which contains adrenalcorticosteroid hormones. Both medullary arterioles and cortical sinusoids merge to form the medullary plexus.
What is the effect of aldosterone secretion becoming zero due to aldosterone deficiency?
large amounts are lost in the urine , not only diminishing the amount of sodium chloride in the extracellular fluid but also decreasing the extracellular fluid volume Severe extracellular fluid dehydration and low blood volume , leading to circulatory shock Results:Without therapy , death within a few days after the adrenal glands suddenly stop secreting aldosterone
What happens with a deficiency of mineralocorticoid?
loss of adrenocortical secretion causes death within 3 to 14 days unless the person receives extensive salt therapy or injection of mineralocortiocids K+ Rises Na+ and Cl- are lost from the body total extracellular fluid volume and blood volume become greatly reduced diminished cardiac output soon develops, which progresses to a shock-like state, followed by death Rx: Adminstration of aldosterone
What method can be used to provide a good clinical indicator of the function of the glands secreting the hormones ?
measurement of the 24-hour urinary excretion of certain steroid hormones or their metabolites
Adrenocorticol hormones are bound by _____
plasma proteins (90-95%) of the cortisol Ex: -cortisol-binding globulin -albumin Binding of cortisol to plasma protein slows the elimination of cortisol from the plasma and creates a longer half life of 60- 90 minutes Note: aldosterone has a relatively short half-life
What are the effects of cortisol on fat metabolism?
promotes mobilization of fatty acids from adipose tissue which cause an increase in the concentration of FFA in the plasma and increase in the ultilization for energy Enhancement in the oxidation of FA in the cells Shift from utilization of glucose to FA in times of starvation or other stressors TAKES HOURS TO DEVELOP
What is the relationship between cortisol on protein metabolism?
reduces protein stores in all essential cells of the body except the liver , reduction is caused by : 1. Decreased protein synthesis 2.Increased catobosm of protein Cortisol mobilizes amino acids from nonhepatic tissues and in doing so diminishes tissue stores of protein. The free amino acids are used for gluconeogenesis in the liver Excess cortisol= weak muscles and skin and connective tissue wasting Reduction in immunity functions
What happens in the absence of aldosterone?
sodium absorption can be poor, leading to failure to absorb chloride and other anions and water as well. The unabsorbed sodium chloride and water then lead to diarrhea, with further loss of salt from the body.
An ultramarathon runner is brought to the emergency tent with extreme exhaustion and muscle pain. The urine is dark in color, but no blood is detected. Serum creatine kinase is critically elevated. The runner is transported to the hospital, where serum potassium and aldosterone are measured. Which of the following are the most likely values? ↑ serum potassium, ↑ serum aldosterone ↑ serum potassium, ↓ serum aldosterone ↑ serum potassium, ↔ serum aldosterone
↑ serum potassium, ↑ serum aldosterone The elevation of serum creatine kinase during extreme exercise indicates rhabdomyolysis (skeletal muscle cell necrosis), which is supported by dark urine due to the presence of myoglobin. Damaged muscle cells release potassium into serum. Hyperkalemia stimulates aldosterone release, in order to promote renal potassium excretion
In response to a physiological stimulus such as the stress of taking an important quiz, which of the following reflects the most likely sequence of events? ↑Cortisol, ↑corticotropin, ↑corticotropin-releasing hormone ↑Corticotropin-releasing hormone, ↑corticotropin, ↑cortisol ↑Cortisol, ↓corticotropin, ↑corticotropin-releasing hormone ↑Corticotropin-Releasing hormone, ↑corticotropin, ↓cortisol ↑Cortisol, ↑corticotropin, ↓corticotropin-releasing
↑Corticotropin-releasing hormone, ↑corticotropin, ↑cortisol Physiological stimuli for glucocorticoids, such as stress, cause the hypothalamic production of corticotropin-releasing hormone (CRH). CRH stimulates corticotropes from the anterior pituitary to release corticotropin (or ACTH). Corticotropin promotes the production of cortisol from the adrenal cortex to help alleviate the physiological stressor.
Which of the following best characterizes the metabolic actions of cortisol? ↑Muscle glucose uptake, ↑muscle amino acid uptake, ↑adipose tissue fat uptake ↑Muscle glucose uptake, ↓muscle amino acid uptake, ↑adipose tissue fat uptake ↓Muscle glucose uptake, ↓muscle amino acid uptake, ↑adipose tissue fat uptake ↓Muscle glucose uptake, ↑muscle amino acid uptake, ↓adipose tissue fat uptake ↓Muscle glucose uptake, ↓muscle amino acid uptake, ↓adipose t
↓Muscle glucose uptake, ↓muscle amino acid uptake, ↓adipose tissue fat uptake The metabolic actions of cortisol increase the availability of circulating fuel sources in response to physiological stressors. Cortisol impairs skeletal muscle glucose and amino acid uptake (although it promotes hepatic amino acid uptake) and promotes lipolysis from adipocytes. This has the net effect to increase plasma glucose, free fa y acids, and amino acids
