Glucose Lecture Flashcards
Ketones
by products of fats that are used to make energy instead of glucose
Ketoacidosis
when the body has a pH less than 7.35 due to the abundance of ketones
ketoniemia
ketones present in the blood
Ketonuria
ketones in the urine
OGTT
oral glucose tolerance test
GDM
gestational diabetes mellatius
Carbohydrates
carbon, hydrogen, oxygen w/ either an aldehyde or ketone configuration
major energy supply
monosaccharides- glucose, fructose, galactos
disaccharides - sucrose (glucose & fructose), lactose (glucose & galactose), maltose (2 glucose)
polysaccharides- glycogen, starch
Amylase
gland in saliva that helps break down starches
stomach acids denature the salivary enzymes
Metabolism of CHO
begins w/ salivary amylase -> stomach acids -> disaccharides in the intestines (lactase, maltase, sucrase bc GI only absorbs monosaccharides) -> monos absorbed-> glucose stored in fat cells or utilized in other cells
Glucose pathways
glucose-6-phosphate :
embden-myerhof pathway (glycolysis)
hexose monophosphate pathway
convert moiety to glycogen
Glycogenesis
conversion of glucose to glycogen
Glycogenolysis
conversion of glycogen to glucose
Gluconeogensis
glucose from non-CHO sources : amino acids etc
Glycolysis
breakdown of glucose to pyruvate or lactate
Glucose clinical reference
ranges : ~80-100 mg/dL
>125 mg/dL during fasting -> suspect diabetes
hemolyzed specimen can alter lab results
insulin
decreases blood glucose (hypoglycemic agent) via aiding in the uptake of glucose into the cells
glucagon
increases blood glucose (hyperglycemic agent)
uses glycogenolysis & gluconeogenesis to increase blood glucose levels
Epinephrine effect on blood glucose
glucose will increase
glucocorticoids (cortisol) effect on blood glucose
stimulates gluconeogenesis particularly to increase blood glucose levels
cortisol breaks down protein so the amino acids will be converted to glucose
growth hormone effect on blood glucose
pituitary hormones
increases blood glucose
ACTH effect on blood glucose
pituitary hormone
stimulates cortisol release (increases)
Thyroxine (T4) effect on blood glucose
increases blood glucose
can speed up metabolism & a loss of T4 can decrease metabolism & can also aid in absorption of glucose in GI tract
Somatostatin effect on blood glucose
can influence growth hormone (ergo increase blood glucose); also known as IGF
protein produced from the liver
Insulin-dependent diabetes mellitus
insulin deficiency, often autoimmune destruction of beta cells of pancreas
affects about 10% of diabetic population
chronic disease effects of diabetes
eyes- retinopathy: optic nerve is especially susceptible to excess glucose
kidneys- renal disease & nephropathy
blood vessels - peripheral neuropathy
ketoacidosis- not enough insulin to utilize glucose & cells start to break down fats
general diabetic symptoms
polydipsia - thirst polyphagia- increased food consumption polyuria - increased urine production rapid weight loss hyperventilation mental confusion ( brain is only getting ketones)
Lab testing for diabetes
fasting glucose >100 mg/dL urine sp. gravity serum & urine osmolalities ketones present blood & urine pH from ketoacidosis electrolyte imbalance hemoglobin A1c
Diabetes type 2
non-insulin dependent diabetes mellitus
may be obesity related
affects 90% of diabetic population
often lack of adequate insulin-receptors on cells or lack of adequate insulin synthesis
Glucose analyzer methods
2 major reactions
B-D-glucose + O2 -(glucose oxidase)-> D-glucono-&-lactone —> gluconic acid + H2O2
use perxoide produced in 2nd reaction:
H2O2 + chromogen –(peroxidase)–>ox-chromogen +H2O2
glucose peroxidase
enzyme used in 1st reaction for glucose analyzing
specifically breaks down specifically beta-D glucose
Perioxidase enzyme
used in many reactions although many things can inhibit the reactions
Hexokinase method for analyzing glucose
glucose + ATP –(hexokinase enzyme)–> Gluc-6-PO4 + ADP
Gluc-6-PO4 + NADP –(G-6-PD enzyme)–> 6-phosgluc + NADPH + H+
most often method used on automated systems
amount of product formed NADPH relates to the amount of glucose in patietn sample
this reaction doesn’t differentiate between beta & alpha glucose orientations
Poloragraphic glucose analyzer method
electrode method that measures O2 consumption by using reaction :
B-D glucose + O2 –(glucose oxidase)–> D-glucono-&-lactone –> gluconic acid + H2O2
eliminates H2O2
Renal glucose limits
> 180 mg/dL in blood glucose will show up in the urine
testing for suspected diabetics
symptoms + random glucose >200 mg/dL
fasting glucose >126 mg/dL
oral glucose tolerance test (OGTT) - where 75g glucose given & wait 2 hours to draw blood-> if value is >200 mg/dL is diabetic (if ~180 mg/dL impaired function not completely diabetic)
must have 2 positive on separate days to diagnose
Hemoglobin A1c
will show glucose control over the last 2 -3 months
based on RBC survival of 120 days
>5.5-6% are out of control
6-7% are acceptable when monitoring diabetics
normal is <5.5%
glucose attachment to the RBC
Monitoring diabetics
monitor for ketoacidosis, acute illness, stress, pregnancy, glucose >300 mg/dL
microalbumin
Microalbumin
increases in urine when kidney glomerulus is damaged
chronic diabetic: 30-299 mg/24hr or albumin/creatinine ratio of 30-300 ug/ml creatine
may see microalbumin increases w/ exercise, infection, fever, increased BP, increased glucose, congestive heart
macroalbuminemia
seen when >300 mg/24 hr or >300 ug/mg creatinine
Hypoglycemia
<60 mg/dL blood glucose
may be due to insulin producing tumor or medications
inborn errors of metabolism leading to hypoglycemia
galactosemia
fructosuria
von Gierke’s
Galactosemia
inborn error of metabolism that may lead to hypoglycemia
decreased galactose-1-phosphatase & cannot utilize galatose as effectively
Fructosuria
inborn error of metabolism that may lead to hypoglycemia -‘fructose in the urine’
decreased fructo-1-phophatase adolase
Von Gierke’s
inborn error of metabolism that may lead to hypoglycemia - affects children glycogen builds up in the liver
decreased glucose-6-phosphatase : liver enzyme used for moving glycogen-glucose into the blood
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