Diabetes, inborn errors of metabolism and superoxides Flashcards
two types of Diabetes + definition
Type 1- insulin dependent
type 2- insulin non-dependent
explain type 1
autoimmune disease where the pancreatic beta cells are destroyed
body thinks the person is in starvation as no insulin is produced but the glucose is still present
type 1 symptoms
hypoinsulinaemia, hyperglycaemia, hyperlipidaemia, hyperkeonaemia
explain type 2
tissues become insulin resistant
due to too much glucose being consumed that the channels no longer respond to insulin
6 major metabolic disturbances due to diabetes melitus
fatty acid mobilisation, hyperketonaemia, hyperglycaemia, polyuria, polydipsia and dehydration
explain fatty acid mobilisation
in type 1
no insulin so body believe ts starving
kick starts beta oxidation
explain hyperketonaemia
body believes its starving
ketone formation and utilisation
ketones are acidic, makes the blood acidic
side effects of hyperketonaemia
diabetic ketoacidosis
nausea, vomiting, smell of acetone
kussmual breathing
dehydration
explain polyuria
more urine produced
less glucose moved into cells
more glucose removed in urine, increasing osmolality
more water leaves body goes to the urine
explain polydipsia
increased thirst as more water leaving the body as urine
normal fasting glucose
4.5-5mmol/L
diabetic fasting glucose
more than 7mmol/L
glucose tolerance test explained
glucose is given and blood samples taken to determine how quickly it is cleared from blood
patient ingests standard dose of glucose and levels checked two hours later
inborn error of metabolism definition
genetic disease where a mutation in a metabolic protein changes its function
two examples of fatty acid metabolism inborn errors
carnitine deficiency and MCAD deficiency
explain carnitine deficiency
carnitine is used to bring fats into the mitochondria via the carnitine shuttle
carnitine deficiency presents with cardiomyopathy
fatty infiltration of cytosol near organs, muscle weakness, hypoglycaemia
explain MCAD deficiency
can’t break down fatty acids during fasting
no ketones produced so no energy source for brain to use during fasting
example of a long chain fatty acid metabolism disorder explained
peroxisomal disorders
unable to break down VLCAs
hypotonia and seizures
explain glycogen storage disorders
deficiencies and mutations in enzymes linked to glycogen storage and formation
leads to exercise intolerance, cramps
what is phenylketonuria?
most common inborn error in metabolism that prevents individuals from being able to metabolise phenyl alanine
phenyl alanine function
converted to tyrosine which can then form fumarate and acetoacetate
why is PKU so damaging?
in high quantities, phenylalanine turns into toxic phenylpyruvate and phenyllactate
phenylalanine outcompetes other molecules for uptake in the brain
PKU treatment
eat less phenylalanine
urea cycle deficiency explained
lack ornithine transcarbamylase
cannot convert carbamoyl phosphate and ornithine to citrulline
increases ammonia concentration leading to death
superoxide definition
a reactive oxygen species
a compound that contains the superoxide ion O2-
how are superoxides produced?
reduction of di oxygen
how is hydrogen peroxide formed?
superoxide and hydrogen ions form hydrogen peroxide and oxygen
hydrogen peroxide function
intermediate when removing superoxides
is hydrogen peroxide toxic?
yes, oxidises potions, membrane lipids and DNA
Important antioxidant
superoxide dismutase
superoxide dismutase function
enzyme that catalyses the partitioning of superoxide into hydrogen peroxide and oxygen
how is hydrogen peroxide broken down?
catalase oxidises the substrate using hydrogen peroxide, producing water
peroxidase definition
enzymes that break up hydrogen peroxide
two antioxidant vitamins
C and E
explain vitamin C function
can reduce and neutralise reactive oxygen species
explain vitamin E function
react with lipid radicals produced in lipid per oxidation chain reactions
