Topic 5 Biochemical activity of Thyroid and Parathyroid hormones
what effect on the kidney can you have if you have hyperparathyroidism?
kidneys would retain calcium and return it in your blood instead of flushing it out through urine. too much calcium in your kidneys can cause kidney stones
are thyroid hormones lipophilic or hydrophilic?
lipophilic. they are hydrophobic
What does Calcitonin do to bone?
(check this) stops osteoclasts from killing bone cells
what is the active form of Vitamin D (3)
1,25(OH)2-D3, Cholecalciferoal or calcitriol
what are the ways to inactivate thyroid hormones
1. T4 to rT3 2. Deiodination (removing the iodine) 3. Decarboxylation (removing the carboxyl group) 4. Deamination (amino group is removed) 5. Glucuronidation (make the hormone soluble in the blood stream so its excreted in the urine.
what are the 5 signs and symptoms of hypothyroidism
1. fatigue 2. weight gain 3. dry skin 4. hair loss 5. constipation
PTH acts on which body parts? (3)
1.osteoclasts 2. kidney tubules 3. intestine
what is the major form of Vitamin D found in the blood?
25(OH)-D3
what does 1-alpha hydroxylase do?
25(OH)D3 is converted to 1,25(OH)2-D3 in the renal tubule
which hormone increases calcium excretion in the urine
Calcitonin
what receptor system does PTH use?
JAK/STAT
what is rT3 and what is the structure?
Reverse T3. Two iodine on the bottom cyclic structure and one on the top. T3 is the opposite
Triiodothyronine
T3
Which thyroid hormone is more active?
T3
Combining MIT and DIT residues on thyroglobulin will form ______
T3 and T4
Is more T4 or T3 produced?
T4
thyroxine aka
T4
What is thyroxin binding globulin and thyroxin binding prealbumin
a carrier protein for T3 and T4
what is subacute thyroiditis
a painful enlarged thyroid from virus or bacteria causes hyperthyroidism
what is calcitriol
active biological form of vitamin D
overactive thyroid nodules can cause _____
amp up thyroid hormone production aka hyperthyroidism
What is graves disease
autoimmune disorder that results in body creating too much thyroid hormone.
which hormone lowers the circulating Calcium and phosphate levels?
calcitonin
function of thyroperoxidase
converts iodide to I+ (iodine)
how does calcitonin act on the kidney tubules?
decreases calcium reabsorption
increased iodine consumption can cause ______ how do you get increased iodine consumption?
eating too much food and medication that contain iodine. causes overstimulation of thyroid aka hyperthyroidism
Are free or bound thyroid hormones more active?
free thyroid hormones are more active
What is the most common cause of hyperthyroidism
graves disease
goiter is a sign of
hyper and hypothyroidism
Weight loss is a sign of
hyperthyroidism
diarrhea is a sign of
hyperthyroidism
hair loss is a sign of
hyperthyroidism
heat intolerance is a sign of
hyperthyroidism
rapid heartbeat is a sign of
hyperthyroidism
cold intolerance is a sign of
hypothyroidism
dry hair is a symptom of
hypothyroidism
puffy face is a sign of
hypothyroidism
slow heartbeat is a sign of
hypothyroidism
where are T3 receptors located?
in the cell in the nucleus.
what does PTH do to the kidneys?
increases calcium reabsorption causes phosphate secretion
what is thyroiditis and what is the effect of it
inflammation of thyroid. causes hyperthyroidism. arrives in 3 ways: 1. subacute 2. postpartum 3. silent
where is Thyroperoxidase found
only in thyroid tissue *
where is calcitonin produced ( gland and cell names)
parafollicular C cells of the thyroid
PTH is first synthesized as ______
prepro-PTH
calcitonin is synthesized as ____
preprocalcitonin
when synthesizing thyroid hormones what does the addition of I+ to thyroglobulin create?
production of thyroglobulin containing Monoiodotyrosyl and Diiodotyrosyl residues
Calcitonin structure
protein of 32 amino acids
what kind of hormone is PTH
protein of 84 amino acids
How do thyroid proteins travel through the blood?
since they're lipophilic they need a carrier protein to get through.
function of PTH
stimulates bone resorption to increase Ca2+ levels and depressing plasma phosphate levels
what does PTH do to phosphate levels?
stimulates phosphate secretion by kidneys
what does Deiodinase do?
target tissues contain this and it will convert T4 to T3
thyroid hormones are produced and secreted by which gland
thyroid gland
Thyroid hormones are synthesized from ___ residues in ____
tyrosyl residues in throglobulin
