Endocrine Flashcards
What is cortisol and where is it produced
Produced by zona fasciculata of adrenal cortex and is the primary stress hormone of the body
What is it regulated by
ACTH in response to stress, decreased level of glucocorticoid, hypoglycemia, inflammation and circadian rhythm
What are some physiologic effects of cortisol
stimulates gluconeogenesis
Decreases translocation of glucose transports( GLUT4) to cell membrane
Help activate glycogen phosphorylase( essential for ability of epinephrine to stimulate glycogenolysis)
Inhibits collagen formation
Decreases uptake of amino acid in muscle
Inhibit protein synthesis
Stimulated secretion of gastric acid
inhibit TNF-a, IL-12, and IFN
Increase production of IL-4, IL-10, and IL-13
Can lead to TH2 dominance
Anti-inflammatory
What is DHEA
Dehydroepiandosterone: produced in zona fasciculata and zona réticulaires of adrenal gland
Precursor to sex hormones
neurosteroid
anti-glucorticoid effects
clinical utility: bone density, depression, decreased libido, erectile dysfunction, CV disease, Cognitive function, infertility, lupus and chronic fatigue
What is GAS
General adaptation syndrome
general theory for animal and human stress response
Provides a means to: recognize environmental triggers and modify them, determine the extent of general adaption, intervene if necessary by various means
What are the 3 parts of GAS
Alarm reaction
State of Resistance
Stage of Exhaustion
What happens in Alarm reaction of GAS
release of cortical hormone into blood stress, depletion in arden-cortical stores, in animals shown decreased body weight, gastric ulceration and atrophy of thymus gland and lymph nodes
What happens in state of resistance stage of GAS
2nd stage of GAS
accumulation of secretory granules of cortical hormones in adrenal cortices
increased body weight, decreased gastric ulceration, general normalization of overall health status
What happens in Exhaustion in GAS
3rd stage
end stage of stress reaction
depletion of hormone-containing granules in adrenal cortices
decreased resistance to stress
correlation with premature aging and exhaustion
mild functional hypoadrenocorticism
What is Maladaptive Stress Syndrome
more recently proposed model of adrenal stress
4 stages: MSS-0, MSS-1, MSS-2, MSS-3, MSS-4
What happens in MSS-0
health well adapted stress responses
varies between hypo vigilance and hypervigilane
levels of vigilance properly regulated by amount of epinephrine and cortisol produced
What happens in MSS-1
correlates with alarm stage in GAS
acute excess of cortisol and epinephrine
considered maladaptive when fight or flight is no appropriate
What is MSS-2
Suppression phase
Chronically elevated cortisol
results in increased levels of norepinephrine
immune and inflammatory responses are suppressed
adrenal androgens often elevated
Conditions: increased sensitivity to mycotic infections, depression, OCD< anorexia, panic disorder, gastritis, hyperlipidemia and others
What is MSS-3
exhaustion phase
deficient glucocorticoid production
decreased production of adrenal androgens
decreased production of mineral corticoids
episodic increases in epinephrine
conditions: hypotension, functional hypoglycemia and others
What disorders are associated with Altered Cortisol Curve
Anorexia Depression Chronic Fatigue ADHD PTSD Hypo and Hyperthyroidism
What are advantages to saliva testing
measures only active unbound hormones makes serial testing easy non-invasive( no blood draw) simple and convenient collection great for children and elderly
What is significant about saliva in testing
bioactive fraction only
only measures hormone that is in tissue
no need to measure binding globulin levels
for cortisol, no increase due to venipuncture
research is still young
What is significant about serum testing
total hormone levels include free and bound fractions
free fraction may not represent level in tissues
binding globulin levels often needed
stress-related cortisol surge may affect accuracy
well-establish in literature and current practice
What is 17-OH Progesterone
produced in zona fasiculata and zona retularis of adrenal
Precursor to Cortisol
What is relationship between cortisol and insulin
cortisol increases blood sugar levels
cortisol excess may result in impaired glucose tolerance, hyperglycemia, hyperinsulinemia
What is relationship between Total SIgA and cortisol
SIga found on mucosal membrane
helps protect from enzymatic degradation
Immune exclusion: binds to antigens and prevents adherence and admittance into body; moderates the mucosal inflammatory response
What are clinical implications of SIgA
Elevated: autoimmune conditions, Diabetes, Gingivities, Apthous ulcers, inflammatory conditions, acute physical or emotional stress
Depressed: chronic stress, allergies, upper respiratory tract infections, celiac disease, selective IgA deficiency
What is Nonclassical Congenital Adrenal Hyperplasia( CAH)
Genetic deficiency of either 21-Hydroxylase or 11B-Hydroxylase
Low cortisol- low tolerance to illness, trauma and other stress
Precursor accumulation( converted to androgen)- acne, oligomenorrhea
May have low aldosterone- syncope, low Na/K ratio and hypotension
Extremely difficult to differentiate from PCOS
What is Cushing’s syndrome
group of signs and sx associated with elevated cortisol
DHEA can be high or low
Abdominal fat, buffalo hump, extremity muscle wasting, thin skin, purple striae
increased risk of recurrent infection, osteoporosis, diabetes, hypertension, kidney stones
What is Addison’s disease
condition with low cortisol, DHEA and aldosterone due to destruction of adrenal cortex
Causes autoimmune disorders, TB, and adrenal tumor
Clinical feature include: fatigue, weight loss, weakness, syncope, salt craving
At risk for acute adrenal crises
What is HPA disturbance W/reverse circadian curvature
Cortisol low in morning and high at night
primary complaint: daytime fatigue, nighttime waking and difficulty falling asleep
associated with delayed sleep phase syndrome
Circadian rhythm disturbances associated with higher risk of obesity, diabetes, and other complications
