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158 Cards in this Set
- Front
- Back
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what is a hormone?
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any substance that carries a signal that ultimately renders some change at the cellular level
produced by one cell which passes through circulation and ellicits effects on other cells/tissues |
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what is an endocrine hormone?
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arise in one tissue or gland and travels through the circulation to reach target cell/tissue of different type
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what is a paracrine hormone?
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hormone which interacts with cells neighboring/near the one which produced it
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what is an autocrine hormone?
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hormone that interacts with cells of identical type to the ones that produced it
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what happens to the visceral fat as it increases?
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becomes more heavily infiltrated by macrophages
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what is the process by which cortisol is released from the suprarenal glands?
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corticotrope releasing hormone stimulates the release of ACTH which stimulates the release of cortisol
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what receptors do the thyroid hormones bind to?
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intracellular receptors (transcription factors)
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what hormones bind to serpentine receptors?
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glucagon
parathyroid hormone leutinizing hormone thyroid stimulating hormone growth hormone releasing hormone |
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what are serpentine receptors?
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g-protein coupled receptors which have 7 transmembrane passes
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what hormones bind to single pass receptors?
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insulin
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what hormones bind to cytokine receptors?
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erythropoietin (EPO)
growth hormone prolactin |
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what hormones bind to guanylyl cyclase-linked receptors?
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atrial natriuretic peptide (ANP)
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what is the POM gene?
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proopioidmelanocortin gene
a gene which provides a variety of hormones depending on what tissue is presenting it |
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why are oxytocin and vasopressin closely related?
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they are very highly conserved proteins, both of which are produced as preproteins and when cleaved supply the hormone and necessary neurophysin
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what are enkephalins?
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endorphins = naturally produced opioid receptor ligands
met-enkephalin and leu-enkephalin, both from the same gene |
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what are hypophyseotropic hormones?
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releasing factors (dopamine and somatostatin are inhibiting factors) secreted into the hypophysial portal blood from anterior pituitary
GRH, TRH, CRH, PRF, GnRH, dopamine, somatostatin, LHRH |
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what are the hormones secreted by the neurohypophysis?
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oxytocin
vasopressin (ADH) |
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to where are hormones delivered from the neurohypophysis?
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directly into the general circulation
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what hormone inhibits the release of prolactin?
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dopamine (prolactin inhibiting factor)
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from what is dopamine derived?
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tyrosine
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how is prolactin release regulated?
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dopamine inhibits the release of prolactin; this is the major form of regulation, rather than something stimulating prolactin to be released
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which hormone inhibits growth hormone secretion?
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somatostatin (growth hormone inhibiting hormone)
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what causes diabetes incipidus?
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deficiency of vasopressin (ADH)
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what is polydypsia?
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excessive thirst
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how are oxytocin and vasopressin produced?
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synthesized as prohormones with hormone and neurophysin
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what is the function of vasopressin?
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regulates body fluid osmolarity
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what is the function of oxytocin?
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contraction of uterine smooth muscle
contraction of smooth muscle of lactiferous ducts neurological reward system |
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by what signalling mechanism do oxytocin and vasopressin function?
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cAMP and PKA or PLCgamma signalling
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what is the function of somatotrophs?
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released from anterior pituitary
target growth hormone secreting cells |
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what is the function of growth hormone?
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induce synthesis of IGFs (insulin-like growth factors)
broadly - stimulate growth of long bones and other tissues |
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what is the function of lactotrophs?
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released by anterior pituitary
target prolactin secreting cells |
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what is the function of prolactin?
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causes differentiation of mammary gland secretory cells
broadly - stimulates milk production |
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what is the function of thyrotrophs?
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released by anterior pituitary
target thyroid stimulating hormone secreting cells |
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what is the function of thyroid stimulating hormone?
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stimulates thyroid production of thyroxine and triiodothyrodine
mainly releases T4 |
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what is the function of corticotrophs?
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released by anterior pituitary
target ACTH secreting cells |
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what is the function of gonadotrophs?
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released by anterior pituitary
targets LH- and FSH-secreting cells |
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what is the function of LH and FSH?
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stimulate maturation, differentiation, and hormone secretion of ovaries and testes
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how does GH effect the growth of long bones and tissues?
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stimulates the synthesis of insulin-like growth factors (IGF-1 and IGF-2)
IGF-1 - postnatal development IGF-2 - fetal development |
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what is the function of ACTH?
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acts on cells of adrenal glands to stimulate the secretion of glucocorticoids, mineralocorticoids, and androgenic steroids
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what is the function of FSH?
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acts on sertoli cells to stimulate sperm production or ovum maturation and estradiol production
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what is the function of leutinizing hormone?
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acts on Leydig cells to increase testosterone
or acts on corpus luteum to increase progesterone |
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what is MSH?
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melanocyte stimulating hormone
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what are the products of the POMC gene in the anterior pituitary?
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ACTH
beta-lipotropin via CRH |
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what are the products of the POMC gene in the intermediate pituitary?
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met-enkephalin
alpha-melanocyte stimulating hormone corticotropin-like intermediate lobe hormone (CLIP) via norepinephrine |
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what are the functions of alpha-melanocyte stimulating hormone?
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stimulates melanocytes
regulates inflammatory responses (stimulates synthesis of IL-10) |
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what are the functions of beta-lipotropin?
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stimulates synthesis of hormone-sensitive lipase in adipose tissue
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what is the function of CLIP?
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corticotropin-like intermediate lobe peptide
hormone which stimulates the release of insulin from beta-cells in the presence of glucose |
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what is the function of beta-endorphin?
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aka met-enkephalin
analgesic effects from cells and neurons by binding nociception receptors |
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what is nociception?
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afferent activity produced in the peripheral and central nervous system by stimuli which have the potential to damage tissue
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what type of hormones are dopamine, norepinephrine, and epinephrine?
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catecholamines
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to what type of receptors do norepinephrine and epinephrine bind?
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alpha- and beta-adrenergic receptors
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to what type of receptors does dopamine bind?
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dopaminergic receptors
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what is the signaling mechanism used by alpha1 adrenergic receptors?
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IP3 and DAG release
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what is the signaling mechanism used by alpha2 adrenergic receptors?
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cAMP and PKA
calcium and potassium channels |
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what is the signalling mechanism used by beta adrenergic receptors?
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cAMP and PKA
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what is the signalling mechanism used by dopaminergic receptors?
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cAMP and PKA
calcium and potassium channels |
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what is the effect of beta-blockers?
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block beta2 adrenergic receptors
(in the vasculature and heart) |
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what are the functions of dopamine?
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pleasure and reward centers in brain
inhibitory neurotransmitter that controls movement |
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from where is dopamine released?
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adrenal medulla
noradrenergic neurons |
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what is the result of disruption in dopamine function?
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psychosis
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from where is norepinephrine released?
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adrenal medulla
CNS and sympathetic nerves of PNS |
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what are the functions of norepinephrine?
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important for attentiveness, emotions, sleeping, dreaming, and learning
blood vessel contraction increases heart rate |
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in what disorders does norepinephrine play a role?
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mood disorders, such as manic depression
why SRI therapy should be coupled with norepinephrine therapy for best effects |
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from where is epinephrine released?
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adrenal medulla, via acetylcholine action and in response to exercise and hypoglycemia
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what is GLP-1?
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glucagon-like peptide-1
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what is GIP?
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gastric inhibitory polypeptide
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what is ghrelin?
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gastrointestinal hormone from stomach and pancreas which stimulates hunger by stimulating synthesis of NPY, resulting in the activation of AMPK
from same gene as obestatin |
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what is obestatin?
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gastrointestinal hormone which stimulates satiety (feeling of fullness)
from same gene as ghrelin counters effects of ghrelin |
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what hormones are part of the pancreatic polypeptide family?
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36aa peptides
pancreatic polypeptide (PP) protein tyrosine tyrosine (PYY) neuropeptide tyrosine (NPY) |
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which of the pancreatic polypeptides are endocrine hormones?
what are the others? |
pancreatic polypeptide (PP) and protein tyrosine tyrosine (PYY) are endocrine hormones
neuropeptide tyrosine (NPY) is a neurotransmitter |
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what is the function of AMPK?
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switches a cell from ATP consumption to ATP production
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what are the functions of pancreatic polypeptide (PP)?
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suppresses glucose-induced insulin secretion
inhibits bicarb and protein secretion from pancreas |
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what are the functions of protein tyrosine tyrosine (PYY)?
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inhibits gastric motility by inhibiting cholinergic neurotransmission
inhibits gastric acid secretion |
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what are the functions of neuropeptide tyrosine (NPY)?
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controls feeding behavior and energy homeostasis
induced by ghrelin creates desire to eat |
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what is the function of the renin-angiotensin axis?
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effect changes in blood pressure
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what stimulates renin to be released? from where?
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drop in blood pressure
from juxtaglomerular cells in the kidneys |
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what is the function of renin?
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cleave angiotensinogen to produce angiotensin I
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where is angiotensinogen produced?
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liver
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what is the function of angiotensin converting enzyme (ACE)?
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cleave angiotensin I to produce angiotensin II
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what are the functions of angiotensin II?
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potent vasoconstrictor
increased vasopressin (ADH) release increased ACTH release |
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what is the major acute-phase protein made by the liver?
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C-reactive protein (CRP)
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what are the adipokines (adipocytokines)?
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leptin
adiponectin resistin (also TNFalpha, IL-6, CRP, PAI-1, MCP-1, visfactin, chemerin, omentin, vaspin, adipsin) |
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what is the only hormone expressed exclusively by adipocytes?
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adiponectin
(other adipokines are released from other cells of the adipose tissue, e.g. macrophages, etc.) |
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why is visceral adipose tissue especially bad?
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the adipokines released from adipose tissue are inflammatory, and if that adipose tissue is visceral, then the organs and vasculature supplying them are affected
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what are the functions of leptin?
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regulates overall body weight by limiting food intake and increasing energy expenditure
regulates neuroendocrine axis, inflammatory responses, blood pressure, and bone mass |
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what is the result of leptin or leptin receptor deficiency?
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obesity (even with no-fat diet)
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why is leptin not the miracle diet drug it was expected to be?
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high levels result in abnormally strong immune responses and predisposes individuals to autoimmune phenomena
in obese individuals, there is a barrier which prevents leptin from getting to the relevant portions of the brain |
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what stimulates the expression and release of adiponectin?
what inhibits the expression and release of adiponectin? |
stimulated by insulin
inhibited by TNFalpha |
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what are the functions of adiponectin?
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exerts inflammatory modulation by reducing the production and activity of TNF-alpha and IL-6
stimulate phosphorylation and activation of AMPK liver - reduces activity of gluconeogenic enzymes & glucose output muscle - increased glucose uptake, fatty acid oxidation, phosphorylation and inhibition of acetyl-CoA carboxylase |
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in what patients are levels of adiponectin reduced?
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obese individuals
patients with anorexia nervosa |
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where is AdipoR1 found?
AdipoR2? |
AdipoR1 - skeletal muscle
AdipoR2 - liver |
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what are the key things to remember about adiponectin?
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antiinflammatory adipokine
enhances insulin sensitivity production reduced in obese individuals phosphorylates & activates AMPK high levels of adiponectin=high fat metabolism |
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what are the key points to remember about resistin?
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secreted by adipocytes
levels increase with adiposity induces resistance to insulin |
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what are the actions of resistin?
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induces insulin resistance
decrease hepatic AMPK activity increase hepatic glucose production reduced glycogen synthesis modulates endothelial cell function by increasing VCAM-1 expression |
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what are the steroid hormones?
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adrenal steroids - cortisol, aldosterone, androstenedione
sex hormones - testosterone, progesterone, estradiol |
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where are the receptors for steroid hormones?
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intracellular receptors
(transcription factors) some are in cytosol and others are in the nucleus |
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what is the intermediate precursor for all steroid hormones?
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pregnenolone (produced directly from cholesterol)
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what are the categories of adrenal steroids?
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glucocorticoids
mineralocorticoids androgens |
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what are the effects of glucocorticoids?
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regulate carbohydrate metabolism, immunosuppressive and antiinflammatory
inhibit PLA2 |
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what are the glucocorticoids?
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cortisol
corticosterone |
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what are the effects of mineralocorticoids?
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regulate sodium and potassium ion excretion (in addition to other electrolytes)
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what are the mineralocorticoids?
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aldosterone
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what are the effects of androgens?
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act similar to male gonadal steroids
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what are the adrenal androgens?
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androstenedione
DHEA |
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to what is DHEA rapidly converted?
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DHEA-S (sulfated DHEA)
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for what is androstenedione a precursor?
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testosterone
estradiol |
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where is aldosterone synthesized?
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from progesterone in the zona glomerulosa of adrenal cortex
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what are the effects of aldosterone?
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increases sodium ion uptake
raises blood pressure and fluid volume |
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what is the dominant glucocorticoid in humans? the dominant mineralocorticoid?
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glucocorticoid - cortisol
mineralocorticoid - aldosterone |
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where is cortisol synthesized?
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from progesterone in the zona fasciculata of the adrenal cortex
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what are the effects of cortisol?
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elevates blood pressure and sodium ion uptake
involved in stress adaptation numerous effects on the immune system |
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how can stress cause insulin resistance?
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cortisol increases lipid metabolism in adipose tissue, releasing it into the blood; since elevated lipid levels cause insulin resistance, chronic/prolonged/recurrent stress can lead to prolonged hyperlipidemia and thereby insulin resistance
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what hormones are produced in each of the levels of the adrenal cortex (from superficial to deep)?
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zona glomerulosa - aldosterone (mineralocorticoids)
zona fasciculata - cortisol, corticosterone (glucocorticoids) zona reticularis - androstenedione, DHEA (androgens) |
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what is the primary hormone responsible for male secondary sex characteristics?
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testosterone
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what is another name for p450c21?
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cyp21A2
21-hydroxylase |
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what is adrenal cortex hypoplasia?
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adrenal cortex is not producing as much of the adrenal cortical hormones as it should
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what is adrenal cortex hyperplasia?
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some aspect of hormone synthesis has run amuck and adrenal cortex is producing too much of its hormones
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what are the three types of disorders in adrenal steroidigenesis?
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addison disease
cushing syndrome congenital adrenal hyperplasias |
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what is addison disease?
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lack of adrenal steroid synthesis (hypoplasia)
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what are the symptoms of addison disease?
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fatigue
weakness weight loss skin pigmentation low blood pressure nausea salt cravings painful muscles and joints |
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what is cushing syndrome?
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adrenal cortex hyperplasia caused by a pituitary tumor
(NOT a congenital adrenal hyperplasia) |
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what are the symptoms of cushing syndrome?
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upper body obesity
excess fat in neck rounded face slender arms and legs fragile, easily bruised skin weakened bones high blood pressure increased thirst, anxiety, depression, and irritability |
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what are the three clinical forms of congenital adrenal hyperplasias?
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salt-losing
simple virilizing attenuated |
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what is the most common cause of congenital adrenal hyperplasias?
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defect in 21-hydroxylase (CYP21A2)
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what is the major feedback inhibitor of ACTH?
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cortisol
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how do symptoms manifest in the salt-losing form of congenital adrenal hyperplasia?
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deficiency in 21-hydroxylase leads to deficiency in glucocorticoids and mineralocorticoids
lack of cortisol drives ACTH release from anterior pituitary increased 17alpha-hydroxyprogesterone diverted to androgens (causing masculinization) lack of aldosterone and cortisol drives salt loss |
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what is the first sign of a congenital adrenal hyperplasia?
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ambiguous female genitalia at birth
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how are symptoms manifest in the simple virilizing form of congenital adrenal hyperplasia?
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21-hydroxylase deficiency not as severe as salt-losing form
aldosterone synthesis compensates for salt loss ACTH high (because cortisol is not produced in sufficient quantity to inhibit anterior pituitary), which drives excess 17alpha-hydroxyprogesterone to produce androgens, which then masculinize female genitalia |
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how are symptoms manifest in the attenuated form of congenital adrenal hyperplasia?
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21-hydroxylase deficiency is only mild, so there is a small excess in production of androgens
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what are the symptoms of the attenuated form of congenital adrenal hyperplasia?
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symptoms manifest at puberty
hirsutism amenorrhea ovarian cysts |
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what is hirsutism?
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excessive growth of thick dark hair in locations where hair growth in women usually is minimal or absent (e.g. face, chest, areolae, axillae)
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what hormone is the primary hormone for secondary sex characteristics in females?
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progesterone
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which hormones regulate ovarian cycles?
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progesterone
estradiol |
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from where is progesterone secreted?
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made directly from pregnenolone and secreted from corpus luteum
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what are the actions of progesterone?
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responsible for changes in luteal phase of menstrual cycle
differentiation factor for mammary glands |
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from where is estradiol secreted?
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produced in and secreted from ovaries
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where is testosterone synthesized?
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95% - Leydig cells of testes
5% - adrenal cortex |
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what is secreted by leydig cells of the testis?
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testosterone
dihydrotestosterone androstenedione dehydroepiandrosterone (DHEA) estradiol, estrone, pregnenolone, progesterone, 17alpha-hydroxypregneolone, 17alpha-hydroxyprogesterone |
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what is dihydrotestosterone?
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DHT
a degradation byproduct of testosterone, which is also a potent androgen |
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what are the functions of testosterone?
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differentiation of external and internal male genitals
stimulates skeletal muscle growth growth of larynx stimulates pubic, axillary, facial hair social behavioral changes |
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what are the two endocrine axes which control testicular function?
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hypothalamic - pituitary - leydig cell axis
hypothalamic - pituitary - seminiferous tubule axis |
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what is the hypothalamic - pituitary - leydig cell axis?
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hypothalamus secretes GnRH
GnRH stimulates release of LH by gonadotrophs in anterior pituitary LH enters Leydig cells and leads to androgen release androgens (mainly estradiol) feedback inhibit hypothalamus |
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how does LH cause androgen release?
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bind G-protein coupled receptor in Leydig cells which leads to increased cAMP, and then to androgen release
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what is the principal inhibitor of GnRH?
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estradiol
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what is the hypothalamic - pituitary - seminiferous tubule axis?
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hypothalamus secretes GnRH
GnRH stimulates release of FSH by gonadotrophs in the anterior pituitary FSH binds to sertoli cells, and induces production of androgen-binding protein |
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what is the function of androgen-binding protein?
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keeps high concentration of testosterone in seminiferous tubules, increasing spermatogenesis
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what is Kleinfelter's syndrome?
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XXY males
most common hypogonadism |
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what is bilateral anorchia?
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male (XY) with no distinguishable testicular tissue
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what is cryptorchidism?
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unilateral or bilateral absence of testes in the scrotum
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what is gynecomastia?
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unilateral or bilateral breast enlargement in males, caused by imbalance in estrogen/androgen levels
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what are the functions of the estrogens?
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maturation of female sex characteristics, genital and breast development
growth of endometrial lining alteration of fat distribution, decrease lipid oxidation, increase TG synthesis decrease bone resorption by antagonizing parathyroid hormone |
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what are the functions of progesterone?
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glandular development in breast
cyclic glandular development of endometrium increases body temperature alters respiratory function |
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what is the function of androgens in females?
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principally testosterone and dihydrotestosterone
normal hair growth conversion to estrogens |
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what is the hypothalamic - pituitary - ovarian cell axis?
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hypothalamus secretes GnRH
GnRH stimulates release of LH and FSH by gonadotrophs in anterior pituitary LH induces androstenedione and testosterone synthesis in thecal cells FSH stimulates aromatase activity in granulosa cells (converting androgens to estrogens) |
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where are the estrogens from thecal cells secreted?
where are the estrogens from granulosa cells secreted? |
thecal cells secrete estrogens into circulation
granulosa cells secrete estrogens into follicular fluid |
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what is amenorrhea?
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lack of menstruation
(could have physical or hormonal causes) |
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what is gonadal agenesis?
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female hypogonadism
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what is Turner's syndrome?
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gonadal dysgenesis due to 45,X karyotype
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