Endocrine Physiology

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paracrine

What are hormones called that act primarily on neighboring cells?

autocrine

What are hormones called that act on the cell that released them?

adipose tissue

growth hormone causes the growth of all tissues except?

bioassay

What is a cumbersome assay that gives variable results depending on the physiological state of the animal, organ, tissue, or cell being used?

radioimmunoassay

An assay is performed in which an Ab to a hormone is used to precipitate hormone, and the amount of radioactive hormone that is precipitated is used to calculate the amount of nonradioactive hormone in the body. What kind of assay is this?

ELISA

An assay is performed in which plastic wells coated with Abs to a hormone bind the hormone. A second Ab recognizes the complex between the first Ab and the hormone. A third Ab recognizes the second Ab, and the third Ab is conjugated to horseradish peroxidase. Then the oxidation of a dye to a differently colored product is measured. What kind of assay is this?

minutes

What is the half-life, in general, of polypeptide hormones?

hours

what is the half-life, in general, of steroid hormones?

seconds

what is the half-life, in general, of epinephrine and norepinephrine?

days

what is the half life of thyroid hormones?

seconds

what is the half-life of prostaglandins, leukotrienes, and NO?

endocytosis

what is the main process of polypeptide hormone degradation in the bloodstream?

forming delta-5-pregnenolone

what is the rate-limiting step in the formation of steroid hormones from cholesterol?

polar in liver

how are steroid hormones removed from the body?

uptake, liver

the two ways in which catecholamines are inactivated?

thyroid follicular cells

in what kind of cells are thyroid hormones produced?

thyroglobulin

What is the large protein containing many tyrosines produced by thyroid follicular cells?

thyroid peroxidase enzymes

What enzymes couple iodine to the tyrosines in thyroglobulin?

T3

What is the more active of the thyroid hormones?

steroid hormones, T3

What types of hormones bind to intracellular receptors that translocate into the nucleus?

adenyl cyclase

What enzyme converts ATP to cAMP when activated by a G protein?

protein kinase A

cAMP binds to the regulatory subunit of what enzyme?

phosphodiesterase

what enzyme helps regulate the cAMP cascade by degrading cAMP?

ER, extracellular space

what are two places from which calcium can be released into the cytoplasm to increase the intracellular Ca2+ concentration?

Protein Kinase C

What enzyme is activated by increased cytosolic calcium?

serine, threonine

What are the two amino acids phosphorylated by protein kinases A, C, and G?

cGMP

What is an important second messenger in the actions of acetylcholine on liver, heart, and smooth muscle?

tyrosine

Some polypeptide hormone receptors (such as the one for insulin) are kinases that phosphorylate proteins an what amino acid residue?

calmodulin

what is the protein that binds to calcium to from a complex that activates other enzymes?

IP3, DAG (inositol triphosphate and diacylglycerol)

fatty acids are degraded by phospholipase C to form what two molecules?

protein kinase C

diacylglycerol directly binds and activates what protein?

Ca release from ER

what does inositol triphosphate do?

ligands

What is another name for signaling molecules?

yes

Is signal transduction by second messengers a flexible process?

amplify

Do second messenger systems amplify or dampen the original signal?

F (signaling is pleiotropic)

T/F one ligand generates one response

adrenal cortex

Where is cortisol produced?

calcium

Vitamin D regulates metabolism of what molecule?

DNA

All intracellular steroid hormone receptors are structurally related and contain a domain that binds what?

heat shock

the inhibitory protein complex normally bound to intracellular steroid receptors often contain what kind of protein?

ion channel-linked, G protein-linked, enzyme-linked

Name the three general kinds of cell-surface receptors.

ion channel-linked

what kind of cell surface receptor is involved in rapid synaptic signaling between electrically excitable cells?

alpha

Which subunit of a G-protein is bound to GDP and has GTPase activity?

Gs

What are G proteins involved in enzyme activation called?

beta-adrenergic receptors

What receptors mediate some of the actions of adrenaline and noradrenaline AND involve activation of adenylate cyclase?

alpha2-adrenergic

What receptors inhibit adenylate cyclase when adrenaline binds to them?

alpha

what subunit differs between inhibitory G proteins and stimulatory G proteins?

protein kinase A (A-kinase)

What protein is present in all animal cells and is thought to account for virtually all effects of the second messenger cAMP?

CREB

What transcription factor is phosphorylated by cAMP, causing it to regulate gene expression in the nucleus?

phosphorylase kinase

What enzyme is phosphorylated by protein kinase A, which then phosphorylates glycogen phosphorylase?

glycogen synthase

What enzyme is inhibited when phosphorylated by protein kinase A, which performs the final step in glycogen synthesis?

I

What serine/threonine phosphatase regulates cAMP response and dephosphorylates many of the enzymes phosphorylated by protein kinase A?

IIA

What serine/threonine phosphatase that has a broad specificity and seems to be the main phosphatase responsible for reversing many of the phosphorylations catalyzed by serine/threonine kinases?

IIB

What serine/threonine phosphatase is called calcineurin, is activated by Ca, and is especially abundant in the brain?

fall

In the visual system, does receptor activation by light cause a rise or fall in cyclic nucleotide?

rhodopsin

What is a seven-membrane receptor activated by light photons instead of molecules?

all-trans-retinal

11-cis-retinal, a chromophore covalently attached to rhodopsin, isomerizes to what molecule when it absorbs a photon?

transducin

Activation of rhodopsin results in activation of G protein _____.

cGMP phosphodiesterase

the alpha-t subunit of G-protein transducin activates this enzyme

cGMP

When this molecule is dissociated from the plasma membrane sodium channels in cells of the eye, they close, converting a light signal to an electrical one.

inhibits

The neurotransmitter released by retinal neurons activates or inhibits neuron?

blocks neuron inhibition

light causes neurons to be inhibited or blocks neuron inhibition?

NO

An intracellular signaling molecule that diffuses across cell membranes and binds directly to guanylyl cyclase to directly regulate its activity.

relax

NO causes smooth muscle cells to do what?

guanylyl cyclase

the enzyme that produces cyclic GMP

Ca-ATPase

A protein found in the plasma membrane of all eukaryotic cells that pumps calcium out of the cell

muscle and nerve cells

What cells have an additional Ca pump in their plasma membrane that couples the efflux of Ca to the influx of Na (Na driven Ca antiport)?

ER

A Ca pump can be found where in addition to the plasma membrane, allowing uptake of Ca from the cytosol even when its level are low?

inner mitochondrial membrane

In the case of rising intracellular calcium due to cellular damage, a low-affinity, high capacity Ca pump found where becomes activated?

phosphatidylinositol

The two most important inositol phospholipid second messengers are phosphorylated derivatives of what molecule, a minor phospholipid in membranes?

PI-phosphate and PI-bisphosphate

The two most important inositol phospholipids.

PI-bisphosphate

The hydrolysis of what inositol phospholipid is very important in signal transduction?

yes

Do G-proteins ever utilize the PIP2 pathway?

phospholipase C-beta

The enzyme that cleaves PIP2 to generate IP3 and DAG.

Gq

The trimeric G protein that activates phospholipase C-beta.

plasma membrane

Protein kinase C translocates from the cytosol to where after the initial rise in Ca levels, where it is activated by a combination of Ca and DAG?

1

Most enzyme-linked cell surface receptors pass through the plasma membrane how many times?

yes

Can enzyme-linked cell surface receptors have phosphatase or protease activity?

tyrosine

Phosphorylation cascades involve two main types of protein kinases: serine/threonine kinases and ______ kinases.

ras

Both kinase linked receptors and G protein linked receptors often activated a small monomeric G protein called ______.

Raf

Kinase bound by ras that activates a kinase cascade including Mek and Map Kinase.

Elk-1

A transcription factor regulated by Map Kinase.

Epo

A cytokine that activates Jak kinases associated with its receptor.

STAT

Activation of a Jak kinase results in recruitment and subsequent phosphorylation of ______ proteins, which then dimerize and translocate to the nucleus to regulate gene transcription.

red blood cells

Erythropoietin (Epo) utilizes the Jak/STAT pathway to increase the production of ________.

SOCS

Proteins activated by STATS to terminate signaling from the Epo receptor.

collecting duct

target tissue of ADH

breast, uterus

target tissues of oxytocin

breast, ovaries

target tissues of prolactin

thyroid

target tissue of thyroid stimulating hormone

ovaries, testes

target tissues of LH and FSH

adrenal cortex

target tissue of ACTH

skin

target tissue of MSH

sensory neurons

target tissue of endorphins

hypothalamus

hormones secreted by the posterior pituitary are synthesized by neurosecretory cells whose cell bodies actually lie in the _____

F (the hormones will return when the axons regenerate and reach new capillary beds)

T/F removing the pituitary will result in permanent of ADH and oxtyocin

osmolarity, volume

increased plasma _____ or decreased plasma _____ will cause ADH release

ADH, oxytocin

the two hormones released by the posterior pituitary

growth hormone

hormone released by anterior pituitary that promotes growth and differentiation of many different tissues

IGF-1 (insulin-like growth factor-1)

in the presence of growth hormone the liver secretes ________, which is what actually causes the growth of most tissues

gigantism

GH excess in childhood leads to ________.

acromegaly

GH excess in adults leads to ______.

insulin

GH triggers lipolysis by reducing adipose tissue sensitivity to ______.

prolactin

A growth hormone-related hormone produced by anterior pituitary that promotes lactation in the breast (and is required for spermatogenesis in men).

prolactin, insulin, cortisol

three hormones required for lactation

oxytocin

hormone required to make milk available to a baby

F (women only)

T/F nipple stimulation results in prolactin release in both men and women

insulin

prolactin and placental lactogen contribute to the ____ resistance that is normally associated with late pregnancy.

glycoprotein

LH, FSH, and TSH are produced by the anterior pituitary and known as ______ hormones

alpha

the ______ subunits for the glycoprotein hormones are similar

corticotrophin

adrenocorticotropic hormone (ACTH), melanocyte stimulating hormone (MSH), and certain endorphins and enkaphalins are produced by the anterior pituitary and known as ______-related proteins

ACTH

the hormone produced by the anterior pituitary that stimulates the adrenal cortex to secrete glucocorticoids

opiate

the endorphins and enkephalins produced by the anterior pituitary have ____-like actions that reduce sensitivity to pain

MSH

the hormone produced by the anterior pituitary that causes darkening of the skin

Cushing's

over production of glucocorticoids causes ______ syndrome

Addison's

under produciton of glucocorticoids causes _______ disease

TRH

Hypothalamic releasing hormone that stimulates release of TSH and PRL

GnRH

Hypothalamic releasing hormone that stimulates release of LH and FSH

SST

Hypothalamic releasing hormone that inhibits release of GH and TSH

Dopamine

Hypothalamic releasing hormone that inhibits release of PRL

CRH

Hypothalamic releasing hormone that stimulates release of ACTH, alpha-MSH, and beta-endorphin

GHRH

Hypothalamic releasing hormone that stimulates release of GH

pulsatile

the hypothalamic releasing hormones and the anterior pituitary hormones they control are released in a ______ fashion to maintain target cell sensitivity to them

night

there is a circadian rhythm to the release of anterior pituitary hormones such that the most hormone is released when?

glucocorticoids

________ suppress ACTH and CRH through a negative feedback mechanism

estrogen

in the follicular phase of the menstrual cycle, ______ suppresses both LH and GnRH release

long

A hormone produced by the target organ inhibits the release of the trophic hormone. This is known as _____ loop feedback.

short

A pituitary hormones directly feeds back to its releasing hormone in the hypothalamus. This is the definition of _____ loop feedback

ultrashort

The ability of some hypothalamic releasing hormones to directly inhibit their own further release is known as ______ loop feedback.

ultrashort

The secretion of GnRH and SST is regulated by _____loop feedback

itself, TSH, GH

SST inhibits the release of

TRH, TSH

T3 inhibits the release of

CRH, ACTH

cortisol inhibits the release of

GHRH and GH

IGF-1 inhibits the release of

SST

IGF-1 promotes the release of

dopamine

prolactin promotes the release of

prolactin

dopamine inhibits the release of

itself

GnRH inhibits the release of

GnRH, FSH, LH

Androgens inhibit the release of

GnRH, FSH, LH

in the follicular phase, estrogens inhibit the release of

GnRH

in the ovulatory phase, estrogens inhibit the release of

GnRH, FSH, LH

in the luteal phase, progestins inhibit the release of

both

Addison's disease can be caused by high or low levels of ACTH?

yes

Will patients with Addison's disease caused by a problem with the adrenal cortex be hyperpigmented?

no

Will patients with Addison's disease caused by a problem in the pituitary or hypothalamus be hyperpigmented?

preproopiomelanocortin

ACTH, alpha-MSH, and beta-endorphin are made from a large precursor (with an equally large name) called ___________

free

Only ionized or "_____" calcium is metabolically active and regulated

PTH (parathyroid hormone)

the hormone responsible for minute to minute regulation of calcium levels in the blood

Vitamin D

the molecule that "fights" the long-term battle for calcium homeostasis and is slower acting than PTH

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