Exam 1 Material Flashcards
what are glycoproteins made of?
2 amino acid chains and carbohydrate subunits
what’s the difference between thymosin alpha-1 and beta-4?
a-1 regulates the immune system (signals release of T-cells from thymus gland), b-4 binds to actin and promotes cell migration (also tissue regeneration)
what are prostaglandins?
Short acting 20 amino acid fatty acid hormones. Produced by almost every tissue in the body. It is a second messenger.
contrast the function of thymosin and thymopoieten.
thymosin promotes the maturation of t-cells and stimulates production of IL2, IL2 receptor, and B-cell growth factor. thymopoietin tells T-cells where to go in the body
[insert thymus hormone] is zinc-dependent.
thymolin
what do leptin and ghrelin do?
ghrelin makes you hungry, leptin makes you hungry
how does estrogen impact T-cells?
a drop in estrogen levels (i.e., menopause) –> activate T cells –> increased inflammation and bone resorption –> development of osteoporosis
what are prohormones?
A precursor to hormones, cleaved in golgi apparatus by proteolytic enzymes.
What is the most abundant type of hormone? How does it enter blood flow?
Peptide/Protein hormones, stored in vesicles and released by exocytosis.
function of thymulin
Zinc dependent, facilitates t-cell differentiation.
non-specific vs specific immunity
non-specific immunity - generalized immunity that all humans are born with (skin, chemicals like stomach acid and tears, generalized white blood cells, like macrophages)
specific immunity - learned by the body based on previous exposure to pathogens (i.e., B-cells and antibodies)
What is Proopiomelanocortin (POMC)?
A precursor to many different hormones. Cleaved by proteolytic enzymes into different pieces that have different functions.
What are the three major ways secretion rate of hormones is controlled?
- stimulating substances, like sugar with insulin
- Neuronal control of endocrine glands (stress/exercise stimulating sympathetic ANS)
3.Other hormones regulating hormone secretion
How were G-Protein’s discovered?
Gilman and Ross studied connection between adrenalin receptors and adenylate cyclase. Used cyc- mutant cell line that bound adrenalin but appeared to lack adenylate cyclase. This was in fact untrue. 1977, Gilman and Ross discovered a GTP binding protein that stimulates adenylate cyclase.
key difference between peptide and steroid hormones?
steroids can enter the cell and bind to intracellular receptors, peptides have to bind to receptors on the plasma membrane
steroids usually require [low/high] affinity binding proteins
low
why is a radioimmunoassay useful?
assesses immunoreactive levels of a hormone since it uses an
antibody to a specific epitope rather than the entire molecule
three major patterns of hormone secretion rate control
- by other substance (increased blood sugar –> insulin release)
- neuronal control
- regulation by other hormones (TRH stimulates release of TSH)
What is a way to measure calcium concentration?
Fluorescent dyes.
what is wrong with mutant forms of ras?
impaired GTPase activity –> excessive growth –> tumors
what does phosphodiesterase do?
turns cAMP into AMP
what does phospholipase C do?
splits PIP2 into DAG and IP3
describe septic shock
bacterial infection –> low blood pressure –> vasodilation –> organ failure
what is the difference between how nNOS, iNOS, and eNOS are regulated?
nNOS and eNOS - highly regulated by calcium concentrations. requires a significant increase in calcium to activate
iNOS - largely calcium-independent due to its high affinity for calmodulin
what is cholesterol synthesized from?
acetyl co-A
_______ is the rate-controlling enzyme in the pathway to synthesize cholesterol.
HMG-CoA reductase
______ occurs from buildup of LDL in/on arterial walls.
atherosclerosis
LDL/HDL (select one) is bad cholesterol.
LDL
_______ is the precursor to all steroid hormones.
cholesterol
3 things cholesterol produce
steroid hormones, bile acids, vitamin D
Describe cholesterol transport in the body.
where do HDL and VLDL assemble?
ER of liver cells
where do chylomicrons form?
intestines
function of HDL
collects (scavenges) cholesterol from non-hepatic tissues and delivers to the liver
function of chylomicron remnants
delivers dietary cholesterol to liver
lipoprotein lipase
a water-soluble enzyme that hydrolyzes triglycerides in lipoproteins, like those found in chylomicrons and VLDLs.
what does PCSK9 inhibitor (repatha) do?
prevents degradation of LDL-receptors –> increases hepatic clearance of LDL –> decreases serum LDL levels
how is CHL excreted?
made into bile salts to be excreted
_____ is the major site for cholesterol synthesis
liver
describe the biosynthesis of cholesterol (five steps)
acetyl CoA —(HMG CoA Synthase)–> HMG CoA –(HMG-CoA Reductase)–> mevalonate —> IPP –> Squalene –> Cholesterol
function of statins
inhibits HMG-CoA reductase, prevents formation of mevalonate and thus decreases biosynthesis of cholesterol
exosomes derived from ______ downregulate blood glucose, treatment for diabetes mellitus
mesenchymal stem cells
what is the consequence of macrophages consuming oxLDL?
formation of foam cell which can lead to atherosclerotic plaques
3 sources of cholesterol
dietary cholesterol, de novo synthesis in liver, extrahepatic tissue biosynthesis
3 major routes of cholesterol leaving liver
secretion of HDL and VLDL, free cholesterol secreted in bile, conversion to bile acids/salts
Lipoprotein
a cluster of lipids, often with a monolayer membrane, together with an apolipoprotein
______ is the main enzyme in bile acid synthesis
7-Alpha Hydroxylase
what does ACAT do?
increases esterification of cholesterol for storage
what happens to cholesterol synthesis when cellular AMP is high?
HMG-CoA Reductase is inhibited by phosphorylation, catalyzed
by AMP-Dependent Protein Kinase. This kinase is active when cellular AMP is high, corresponding to
when ATP is low.
describe translational control of cholesterol
SREBP, a transcription factor, binds to SRE (sterol regulatory element). When sterol levels are low, SREBPs
are released by cleavage of precursor
proteins in ER membranes. translocate into the nucleus
where they activate transcription of
genes for HMG-CoA Reductase
Enzymes which produce steroid hormones from cholesterol are located in _____ and _____
mitochondria and smooth ER
true or false: steroid hormones are water-soluble and thus do not need binding proteins
false—they are not water-soluble and have to be carried in the blood complexed to specific binding globulins
what is an example in which a steroid is secreted by one cell and is converted to the active steroid by the target cell?
an example is androgen which secreted by the gonad and converted into estrogen in the brain
______ is precursor
to all steroids, except
calcitriol
Pregnenolone
true or false: steroid hormones are usually secreted as they are
synthesized
true
Cholesterol synthesis ______ when ATP levels are low and ______ when ATP levels are high
decreases; increases
5 types of steroid hormones
glucocorticoids, mineralocorticoids, androgens, estrogens, progestogens
example of androgen
testosterone
function of progesterone
prepares uterus lining for implantation of ovum
glucocorticoids example and function
cortisol
promote gluconeogenesis; favor breakdown of fat and protein; anti-inflammatory
Mineralocorticoids example and function
aldosterone
maintains blood volume and blood pressure by increasing sodium reabsorption by kidney
where is estrogen produced?
ovaries primarily but also in adipose
cells of males and females
the ______ zone (zona ______) of the adrenal gland produces aldosterone
outer; glomerulosa`
the ______ zone (zona ______) of the adrenal gland produces cortisol
middle; fasciculata
the ______ zone (zona ______) of the adrenal gland produces corticosterone and androgens
inner; reticularis
______ stimulates the release of LH and FSH from the pituitary gland
Gonadotropin-releasing hormone (GnRH)
what happens if 17-hydroxylase is absent in the steroid synthesis pathway?
hyperaldosteronism (high salt content and increased blood pressure
function of sertoli cells
synthesizes ABP (androgen binding protein) in testes, along with some growth factors for sperm cells). ABP combines with testosterone to allow for sperm cell production
____ stimulates sertoli cells to synthesize ___
follicle-stimulating hormone (FSH); androgen binding protein (ABP)
____ stimulates leydig cells to synthesize ___
luteinizing hormone (LH); testosterone
______ is involved in rate limiting transport of cholesterol into
mitochondria
StaR protein
function of 5-alpha reductase
converts testosterone to DHT, which allows for differentiation of external genitalia in men
function of aromatase
converts testosterone to estradiol, which allows for differentiation of a male hypothalamus
what happens if there is a mutation in 5-alpha reductase?
internal male reproductive organs (testes) but no external genitalia
function of ACAT
converts cholesterol into cholesteryl esters, which are stored in cells as lipid droplets. reduces steroid synthesis bc that pathway relies on free cholesterol.
the ______ is a system of blood vessels connecting the hypothalamus with the ______ pituitary
hypophyseal portal; anterior
the ______ is a bundle of axons that connects the hypothalamic nuclei with the ______ pituitary.
hypophyseal tract; posterior
true or false: amino acid sequence modification results in minor modifications to zinc finger structure resulting in selective binding to DNA
true
hormone response element
short sequence of DNA within the promoter of a gene that is able to bind to a specific hormone receptor complex and therefore regulate transcription
An intracellular nuclear receptor (NR) is located in the cytoplasm bound to a _______
heat shock protein
7 hypothalamic hormones
GnRH, CRH, TRH, PRH, dopamine, GHRH, somatostatin
the paraventricular nucleus of the hypothalamus contains _____ and _____ neurons
magnocellular and parvocellular
the supraoptic nucleus of the hypothalamus contains only ____ neurons
magnocellular
The magnocellular neurons of the PVN and SON synthesize _______
vasopressin
vasopressin is also known as ____
anti-diuretic hormone (ADH)
