Anterior Pituitary Hormones

What are the five hormones made in the hypothalamus that get transported to the median eminence for transport across the anterior pituitary?

-Growth hormone releasing Hormone (GHRH)

• Somatostatin (GHIH)

-Dopamine

-Adrenocorticotropin releasing hormone (ADCRH)

-Gonadotrope releasing hormone (GRH)

-Thyrotrope releasing hormone (TRH)

what are the 5 cell types in the anterior pituitary?

-somatotrophs

-gonadotrophs

-lactotrophs

-thyrotrophs

-corticotrophs

what are the 5 hormone types made in the anterior pituitary?

1) corticotropin

2)FSH and LH

3)TSH

4)prolactin

5)growth hormone

Binding of TRH to the Galphaq receptor on a thyrotrope creates

TSH

What receptor does TSH target on your thyroid? What hormones are created as a result?

Galphas

-T3,T4, and calcitonin

What hormones are produces by the attachment of FSH and LH to the Galphas receptors on your gonads?

P4, E2, and testosterone

what percentage of gonadotrophs can create both FSH and LH hormones?

60%

what percentage of gonadotrophs are specific to FSH production?

22%

what percentage of gonadotrophs are specific to LH production?

18%

Why is progesterone percentages higher during pregnancy?

to prevent spontaneous abortion

Corticotrope cells can create what hormones? what are these hormones a precursor for?

-POMC hormones (proopiomelanocortin derived hormones)

-they serve as the precursor for ACTH, B-endorphin, and MSH

MSH

-created from the precursor POMC using corticotrophs

-targets melatonin

-targets MCRI

MCRI

the Galphas receptor on a milanocyte

an influx of MSH can cause

skin cancer

B-endorphins

-a natural opioid

-attaches to your opiate receptors

-high in childbirth and prolonged exercise

ACTH

-stimulated by stress

-released in pulses

-targets the adrenhal cortex

-production of glucocorticoids and mineralocorticoids

glucocorticoids

-regulate glucose metabolism

-ie cortisol

mineralocorticoids

-regulate mineral metabolism

-ie aldasterone

somatotropin is also known as

growth hormone

somatostatin is also known as

growth hormone inhibiting hormone

when does the largest release of growth hormone occur?

during slow wave sleep

-the reason kids can sleep for longer

regulators of growth hormone

-dopamine

-estrogen

-cortisol

-androgens (sex hormones from the adrenal gland)

what causes inhibition of growth hormones?

extreme stress

what does the body do to increase the half life of growth hormone?

it releases it inactive and attached to a chaperone to prevent binding and activation until it reaches its destination

where are growth hormone receptors found?

-liver

-bone

-kidney

-adipose

-skeletal muscle

-heart

-brain

-immune cells

How does growth hormone effect your bones?

-in long bones, GH targets your epiphyseal plates and elongates the bone

-short bones and bone turnover

what happens if there is too much growth hormone in your bones?

your short bones grow too far and begin to get you exaggerated features

(extremely long chins and fingers)

when growth hormone targets adipose (fat deposits), what happens in your body?

-if there is a decrease in glucose intake, increased lipolysis occurs

-why children can eat alot

lipolysis

breaking down fat

what effect does growth hormone have on your skeletal muscle?

-helps proliferate muscle mass

-decreases protein degradation and synthesis

-amino acid uptake

-anabolic effects

what does growth hormone do to the counts of immune cells in your body?

it increases them

the effect of growth hormone on eyes, brain, and cardiac tissue

-efficient synapses

-proper signaling

-helps with further development

what does growth hormone do in the kidneys?

increases nephron development

What is the hormone created by growth hormone presence in the liver?

Interleukin growth factor (IGF)

what function does IGF trigger and what is it considered?

mitosis, a mitogen

What does IGF do?

-aids in apoptosis

-increases bone cells

-help with neural growth

if IGF counts were depleted,

development (mental, muscular, etc) slows

what is the receptor for IGF attachment?

IGF receptor

-a heterotetrametric with alternating alpha beta subunits like a hemoglobin

-the IGF binds at the ALPHA subunit and causes downstream effects

when pregnant, what happens to estrogen and progesterone?

estrogen depletes but progesterone is increased

progesterone

stimulates dopamine and allows it to bind to Galphai and inhibit the release of prolactin

if dopamine is seen in high levels, it can be assumed that

prolactin is not being released and the person is preggers

After birth

estrogen levels are high, dopamine is very low, prolactin can be released allowing milk production

prolactin receptors

-a single membrane protein that binds exteriorly

-found in the mammary gland, brain, and ovaries

-allows you to secrete milk

Dopamine in the hypothalamus

-Associated with associative learning

-pleasure behavior

the precursor for dopamine is

L-dopa

if you have too much or too little L-dopa

you are at risk of developing schizophrenia or parkinsons

patients with parkinson’s are commonly more susceptible to what other disorder?

schizophrenia

hypopituitarism

-low counts of anterior pituitary hormones due to genetics, injury, or bloodless in the brain

-most commonly causes deficiency in GH, FHS, and LH

Laron Syndrome

growth hormone insensitivity due to a mutated receptor

-short people

function of the thyroid is to

-maintain energy homeostasis and expenditure

-stimulation of cell metabolism and activity

what do you call the area that connects the right and left sides of the thyroid together?

the isthmus

how heavy is the thyroid?

10-25 grams

what is a colloid?

the middle area of a thyroid follicle

summarize the steps of T4 production

-Sodium and iodide is released from the bloodstream into the thyroid follicle using a symporter

-A pendrin on the apical membrane allows iodide to move into the colloidal space and become iodine

-thyroglobulin (Tg) is released in the follicle

-TPO (thyroid peroxidase) sticks the iodine onto the thyroglobulin in a very specific way to create T4

-T4 released into the bloodstream using MCT (Monocarboxylate transporter)

T4

thyroglobulin+4 iodines

=thyroxine

T3

tri-iodothyronine

T2

di-iodothyronine

monoiodothyronine

T1

why do we release T4 more than T3?

because T4 can be cleaved into T3 later on, longer half life, but T3 is the portion we use

out of the thyroid hormones produced, 80% of hormones released are

T4

-T4 then becomes deionized to T3 to be used

Thyroglobulin

a glycoprotein that is transported across the basolateral membrane into circulation

Graves disease

noniodinated thyroglobulin, T3, or T4

what prevents your iodine in blood from getting too high?

the Wolff-chaikoff effect

-iodide can sit inside of the cells and colloid without being released

-down regulation of pendrin

T4 must be DE-iodinated on which carbon to become T3?

on the 5th carbon

HRE

hormone response element

-where T3 binds

why would we convert T3 to T2?

for hypothalamic feedback

where does T3 and T4 bind in the liver?

onto LDL receptors

areas to go back and relook at

thyroid and liver

What is the impact of T3 on the heart?

-increased T3 in the body causes upregulation of adrenoceptors

-no binding needed

beta adrenergic receptors

most common, causes increased binding of epinephrin and norepinephrine

epinephrine

-created in the medulla of the adrenal gland

-stimulates the heart, faster heartbeat, nervous

since the addition of T3 causes the increase binding of norepinephrine, what can be said about the effect that T3 has on the heart?

it causes your heart to beat faster, increasing stroke volume, cardiac output, and blood pressure

-more blood gets pumped out in one pump

the presence of thyroid hormones in the CNS does what?

increases dendrite and myelin sheath production, and synaptic activity by targeting calcium channels

-allows for better communication

what effect do thyroid hormones have on your bones?

they target osteoblasts and osteoclasts and aid in balance between growth and destruction

-allows for reformation, growth, and remodeling

calcium must be maintained where?

in the blood

what effect does thyroid hormones have on your adipose?

an increase in thyroid hormone causes an increase in lipolysis as a source of energy

-glycerol is moved to the liver for gluconeogenesis

anabolism

building up muscle

catabolism

breaking down muscle

Layers of the skin in order from the outside to in

Stratus:

courneum

Lucidium

Granulosum

Spinosum

Basali

what is the thickest layer of your skin?

the stratus lucidium

what does thyroid hormone do to skin?

it causes dilation of the vessels near the skin and increases sweating and body temperature

What do thyroid hormones do in your digestive system?

it targets cells right outside your digestive tract and aids in secretions to help your poop move

someone who is hyperthyroid, their bathroom habits would be

pooping frequently, diarrhea

what are the three ways thyroid hormones can cause disease?

1) not enough T3 or T4

2) Something is mutated, hormone or receptors

3)issues on the level of the hypothalamus

Someone with hypothyroidism may experience

-weight gain, low metabolism, lethargy

what are the two ways someone can have hypothyroidism?

1) Levels of T3 and T4 are good but extreme low levels of TSH

2) Levels of T3 or T4 are low and TSH levels are high

Euthroid sick syndrome

an illness someone with hypothyroidism would get

-Caused by levels of nonbioactive T3

Caused by:

-extreme stress, pneumonia, and kidney/heart failure

Hashimoto’s disease

An illness experienced by women with hypothyroidism

-Autoimmune, your immune cells attack your thyroid gland

-extremely low T3 and T4 production

-most common in middle aged women

Symptoms of Hyperthyroidism

weight loss, extremely fast metabolism, nervous, hyper

graves disease

an illness that a patient with hyperthyroidism may experience

-caused by an infection and high iodine levels

-weak muscles, bulging eyes, blindness, muscle apathy

-treated with radioactive iodine