Lecture 12 Information Flashcards
Hormones
signaling molecules that travel from one area of the body to another
Metazoans
have different tissues that accomplish different jobs and need to communicate to each other
What controls hormones?
the neuro-endocrine system
Soluble hormones
have polar groups and can interact with water
interact with extracellular receptors
signals are amplified and work fast
Insoluble hormones
nonpolar groups and can travel through the membrane
interact with intracellular receptors
signals have a slower response than soluble hormones
Insulin
peptide hormone
decreases sugar concentration in the blood
Preproinsulin gets clipped twice to become mature, active insulin
Store insulin in vesicles that can be released through exocytosis
Example of a peptide hormone
insulin
Catecholamine hormones
water soluble (bind extracellularly)
Named after “catechol ring” that is base (2 -OH groups on benzene)
Highly concentrated in secretory vesicles released through exocytosis
Example of catecholamine hormone
epinephrine
Eicosanoids
all made from arachidonate (type of fatty acid)
produce as needed (unlike peptide and catecholamine hormones)
Examples of eicosanoids
prostaglandin, thromboxanes, leukotrienes
Steriod hormones
4 fused ring structure
all derived from cholesterol
travel to target tissue through blood on protein carriers
all act through internal receptors
Examples of steroid hormones
Progesterone, testosterone, cortisol, estradiol, aldosterone
Vitamin D Hormones
produced in our skin as a result of UV light hitting our skin
Liver and kidneys then produce the final form we use in our bodies
Retinoid hormones
beta carotene is needed to make these (obtained through diet)
beta carotene is converted to Vitamin A (retinol) and retinoic acid
retinoic acid is used for signaling between cells during development
Thyroid hormones
T3 and T4 type of thyroid hormones
plays an important role in our metabolism
interact with receptors on our thyroid (mediated by g-proteins)
hormones are released through proteolysis on a need-based basis
Difference between T3 and T4 hormones
how many iodines are attached
Nitric oxide
a gas
made by NO synthase from arginine
acts on cells near its production site (not long distance)
Which types of hormones are made from lipids?
steroids, eicosanoids, vitamin D, retinoid
Which types of hormones use intracellular receptors?
steroid, thyroid, vitamin D, retinoid, NO
Which types of hormones are made in advance of signaling and stored?
peptide and catecholamine
Which types of hormones have ring structures?
steroid, catecholamine, thyroid and some eicosanoids
Central nervous system
orders the endocrine system to make hormones
top-down control
goes from central nervous system to hypothalmus to two parts of pituitary gland
Liver
metabolic superhero that can quickly change its response to different signals
liver processes materials and filters toxins that come into our body
How do nutrients get to our liver?
through the circulatory system
Hepatocyte
refers to liver cells
What signal do hepatocytes respond to in order to release more glucose into the blood stream?
glucagon
What signal do myocytes respond to in order to release more glucose into the blood stream?
epinephrine
myocytes
refers to muscle cells
Glycogen phosphorylase
breaks a glucose off of glycogen on the nonreducing end
glycogen phosphorylase is activated through a phosphorylation cascade
How does glucose get released from glycogen?
cAMP is produced from adenlyl cyclase
cAMP activated PKA which then triggers a phosphorylation cascade
What happens to glucose in the bloodstream?
glucose is taken up by other cells through hexokinase
hexokinase transforms glucose to glucose 6-phosphate
glucose 6-phopshate gets converted to glucose 1-phosphate and then goes to glycogen for storage
What triggers glucose to be uptaken by cells?
insulin
decreases blood-sugar concentration
What happens when carbs interact with the liver?
GLUT2 transporter brings glucose into the liver
Glucokinase turns glucose into glucose-6 phosphate
Glucose-6-phosphate is a central metabolite used in a variety of pathways
Glucokinase
converts glucose into glucose-6 phosphate
has a high Km (low binding affinity)
will not use glucose unless neccessary, does not bind glucose when glucose concentration is low
Glucose 6-phosphate
a central metabolite used in MANY different pathways
Main pathway is to be turned into pyruvate and then acetyl coA to be used in citric acid cycle
What happens when amino acids meet the liver?
amino acids/proteins are used as a source of protein when the body is in starvation mode
can take off amino acid section to leave two carbons that can be used for acetyl coA or pyruvate for energy production
Where does amino group go when broken down in the liver?
the amino group goes to urea to be disposed as waste in urea
What happens when lipids meet the liver?
lipids are usually used as fuel to make ATP
lipids are also converted to membranes
lipids can be made into ketone bodies to be sent off to other tissues
How are lipids converted to fuel in the liver?
through beta-oxidation they are converted to two carbon units to be used as acetyl coA
beta oxidation reduces FAD to FADH2 and oxidizes the lipid
What do neurons use for energy?
glucose
need glucose to power the sodium-potassium pump to move ions against their concentration gradient
Adipose cells
store triaglycerides (fat)
White adipose cells
store a huge droplet of fat
used for storage
brown adipose cells
store more mitochondria and less triaglycerides
used to generate HEAT through breaking down triaglycerides
fat is broken down through beta-oxidation to make acetyl coA for energy production
energy produced by classic method in the mitochondria
Thermogenin
uncoupling protein used in brown adipose cells
fits into the mitochondrial membrane and disrupts the protein concentration gradient
generates heat
Posterior pituitary gland
hypothalmus uses neurons to send vesicles full of vassopressin and oxtyocin to the posterior pituitary gland
then, posterior pituitary gland sends vassopressin and oxtyocin into the bloodstream
Anterior pituitary gland
hypothalmus sends signals through the blood vessels to interact with the anterior pituitary gland
What process breaks down insulin into its functional form?
proteolysis
What amino acid are catecholamines derived from?
tyrosine
What amino acid is nitric oxide derived from?
arginine
What type of hormones does anterior pituitary gland release?
tropic hormones
What does hypothalmus produce and release?
releasing factors
What is the preferred fuel for skeletal muscles?
fatty acids
What can replentish ATP in muscle cells?
phosphocreatine
What produces lactate?
cori cycle
What does brain use as energy source?
prefers glucose but can use ketone bodies in desperate times
What does insulin inhibit?
glycogen phosphorylase
prevents glycogen from being broken down to glucose
