Glucose Regulation, relevant hormones, and Diabetes Flashcards Preview

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Flashcards in Glucose Regulation, relevant hormones, and Diabetes Deck (49)
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What hormones are primarily responsible for decreasing blood glucose and for increasing it?

insulin and glucagon


What processes does glucagon stimulate and inhibit?

stimulates glycogenolysis and gluconeogenesis; inhibits glycolysis


name 3 secondary hormones that deliberately cause an increase in blood glucose levels; which two are insulin antagonists?

cortisol, epinephrine, and growth hormone. cortisol and growth hormone are insulin antagonists.


what does cortisol do?

regulates carb, fat & protein metabolism; water and electrolyte balance; suppresses inflammation ad allergic reactions


In what disease is cortisol elevated and has lost diurnal variation (meaning higher in morning)?

Cushing's syndrome


differentiate between Cushing's syndrome and Cushing's Disease:

Syndrome: Body has made too much cortisol over a long period

Disease: pituitary tumor causing overproduction of cortisol; is cause of ~ 70% of Cushing's Syndrome caused endogenously


What hormone regulates the release of cortisol? Where is cortisol and this stimulating hormone made?

ACTH: adrenal cortex (outer layer) and anterior pituitary


Describe in simple terms the pathway from gland to gland in production of cortisol

The hypothalamus produces corticotropin-releasing hormone (CRH) which stimulates the anterior pituitary to produce adrenal corticotropic hormone (ACTH); which stimulates the adrenal cortex to release cortisol


What are the 4 major adrenal hormones? which are made in the cortex and which in the medulla?

aldosterone, cortisol, and epinephrine and norepinephrine;  The first two in the cortex, the latter two in the medulla


what are the catecholamines, their purpose, and their metabolites? Test specimens for each?

Epinephrine and norepinephrine; They stimulate the sympathetic nervous system in flight or flight syndrome; metabolites are metanephrines and VMA (vanillylmandelic acid); plasma and urine for catecholamines and metanephrine; urine for VMA


what does aldosterone do and where is it made?

Aldosterone’s primary function is to act on the late distal tubule and collecting duct of nephrons in the kidney, directly impacting sodium absorption and potassium excretion; made in adrenal cortex 


describe in simple terms the renin-angiotensin-aldosterone-system

JG cells of kidney are stimulated by low BP or decreased sodium to produce renin--> renin in bloodstream activates angiotensinogen which is in plasma, coming from the liver--> now angiotensinogen is cleaved into Angiotensin I--> AT I gets converted by ACE in lungs or kidneys into AT II.  

AT II binds various organs' AT receptors (incl adrenal gland, brain, kidney, arterioles); net effect is sodium reabsorption and thus blood osmolarity increase, with increase in BP


List 10 things increases in uncontrolled Diabetes mellitus

Blood glucose, urine glucose, urine specific gravity, Osmolality of blood and urine, glycohemoglobin (A1C!!), and ketones;

Anion gap, BUN, , cholesterol, and trigs


what lab values are decreased in uncontrolled diabetes mellitus?

bicarbonate, and pH (more acidic)


what is considered positive for diabetes mellitus in a random plasma glucose reading?

> 200 mg/dL


what is considered diagnostic of diabetes mellitus with regards to fasting plasma glucose?

8 hours minimum fast; on greater than 2 occasions BG > 126 mg/dL


what is considered diagnostic of DM in regards to a 2-hour plasma glucose test given a 75 gram glucose load?

same as a random, > 200 mg/dL


WHat is the oral glucose tolerance test used to diagnose and what are the parameters of diagnosis?

gestational diabetes, done at 24 to 28 weeks; fasting, if > 92mg/dL ;  1 hour, > 180 ; 2-hr >153


what is the cutoff for A1C for diabetes diagnosis?

 > 6.5%


what is the average reference range for normal fasting blood glucose?

70 to 99 mg/dL


How can the metabolism of blood glucose in specimens be prevented in order to not get a falsely lower reading? what changes are expected if blood is at room temperature?

chilling sample in ice water (slurry) or use of flouride in unseparated samples (it is a glycolytic inhibitor);   Glucose levels fall by 2 to 3 % per hour at normal RT


common methods of analyzing blood glucose: 

enzymatic using either glucose oxidase or hexokinase


what is the main form of lipid storage and what common methods are used to measure?

Triglycerides; enzymatic methods using lipase on fasting specimens


WHat can be measured in the urine of diabetics to help predict nephropathy? Why not just test albumin?

microalbumin; can be detected earlier than dipstick protein (includes albumin)


how is microalbuminuria measured?

by immunoassay on a 24 hour urine specimen


what levels of microalbuminuria are predictive of diabetic nephropathy?

50 to 200 mg/24 hr


In what condition, mainly,  does albumin concentration increase?



In what conditions does albumin concentration in the blood decrease?

malnutrition, liver disease, nephrotic syndrome (loss), chronic inflammation


what is the reference range for albumin?

3.5 to 5 g/dL


what protein is the largest fraction of plasma proteins? what are its functions?

albumin; mainly regulation of osmotic pressure, but also can carry some vitamins and hormones, fatty acids, bilirubin, ions, drugs.......