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96 Cards in this Set
- Front
- Back
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How do we measure hormones concentrations?
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By radioimmunoassay
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What is the general method of the assay done for measuring hormone conc?
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Mix known amount of Ab to hormone, Labeled ligand hormone, and the unknown serum sample. Compete for binding; measure how much labeled hormone is left free
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So what will detection of high levels of free labeled hormone indicate?
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The serum sample contained lots of patient hormone that outcompeted the labeled ligand; so it's left free in the tube.
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How do you know how many binding sites are AVAILABLE to the sample hormone and labelled hormone?
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You put the antibody in there; you know the concentration.
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How is the assay plotted graphically?
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With a standard curve - ratio of bound:free labeled hormone (y) vs conc of patient hormone (x)
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What do high levels of bound:free labeled hormone mean?
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High up on the curve to the left - low levels of patient hormone
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How are hormones synthesized? Where?
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As Preprohormones - on rought ER
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What are PROhormones?
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Products of cleavage of Preprohormones
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What gets released on the process of cleaving Preprohormones into Prohormones?
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Signal peptides
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Where does the Prohormone go?
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To the Golgi
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What happens to the Prohormone in the golgi?
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More cleavage produces the actual HORMONE that gets packaged into secretory granules for later release.
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What are Steroid hormones synthesized from?
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Cholesterol
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What are Amine hormones synthesized from?
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Tyrosine
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What are the amine hormones?
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-Epinephrine
-Norepinephrine -Thyroid hormone |
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What is the most COMMONLY applied principle method for regulating steroid hormone production?
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Negative feedback - self limiting!
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To illustrate NFB, what stimulates and inhibits Insulin secretion? From where?
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-Increased blood glucose stimulates B-cells in pancreas to release glucose
-Decreased blood glucose inhibits insulin release |
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And how does the blood glucose decrease to inhibit insulin release?
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That's the effect of insulin
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What is Positive feedback?
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Rare and EXPLOSIVE! Self REINFORCING
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Most common example of Positive feedback:
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Estrogen positive feedback on ant pituitary just before ovulation - causes the LH surge
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What effect does LH have in response to stimulation from estrogen during the LH surge?
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Stimulates MORE estrogen secretion from the ovaries
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How do hormones regulate the sensitivity of target tissues?
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By regulating the Number of receptors (sensitivity)
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What are 2 ways that hormones can regulate #/sensitivity of receptors?
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1. Down-regulation of receptors
2. Up-regulation of receptors |
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What is an example of DOWNregulation of receptors?
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Progesterone down-regulates its own receptor and the Estrogen receptor on the uterus
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What is an example of UPregulation?
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Estrogen UPregulates its own receptor and the receptor for LH
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What are the 5 signal transduction mechanisms that hormones can employ?
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1. cAMP
2. IP3 3. Intracellular steroid mech 4. Tyrosine Kinase linked (TKLR) 5. cGMP |
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What transduction mechanism do MOST hormones employ?
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cAMP
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What are 7 hormones that employ the IP3 mechanism?
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-GNRH, GhRH, TRH,
-Ang II, ADH -Oxytosin -a1 receptors for Epi/NE |
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What are the steroid hormones?
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GET PAT Very dry
GH, Estrogen, Testosterone, Progesterone, Aldosterone, Thyroid hormone, Vit D |
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What 2 hormones act by Tyrosine kinase linked mechanisms?
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IGF1 and Insulin
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What hormones use the cGMP transduction mechanism?
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GANE
-ANP -Nitric oxide -EDGF |
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How do all G proteins, whether Gs or Gi, stop their activity?
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By intrinsic kinase activity
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What breaks down cAMP after it is increased by Adenyl cyclase activity?
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Phosphodiesterase
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What inhibits PDE and thus maintains high levels of cAMP?
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Caffeine/Theophylline
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What are the 2 things that a hormone causes when it binds to a Ca-Calmodulin transduction mechanism -linked receptor?
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1. Opens surface Ca channels
2. Releases Ca from ER |
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What does all the increased Ca in response to hormone binding then do?
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Binds CALMODULIN and together they have effects.
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Why don't Steroid hormone receptors just bind DNA automatically? They're allready intracellular or intranuclear..
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Because the binding of hormones is what causes a conformation change, allowing them to bind to DNA-binding domains.
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How does Vit D's activation of gene expression and protein synthesis affect physiology?
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It upregulates a CALCIUM BINDING protein so that intestinal absorption is increased!
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How is the Pituitary linked to the Hypothalamus?
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By the hypothalamic-hypophysial portal system
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Why is this portal system good?
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Blood rich in Hypothalamic hormones is delivered right to the pituitary (Hypophysis)
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What PART of the pituitary is linked to the hypothalamus by this portal system?
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ONLY the anterior!
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What is the posterior pituitary derived from?
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Neural tissue
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Where are the nerve CELL BODIES in the posterior pituitary located?
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In the HYPOTHALAMUS
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What does this mean?
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Hormones are MADE in the hypothal, then go down the axons to be RELEASED from post pit
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What cells secrete GH and Prl in the pituitary?
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Acidophils
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What 3 hormones belong to the SAME glycoprotein family? How are they related?
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-TSH
-LH/FSH They all have the SAME ALPHA SUBUNIT |
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So what confers unique biologic activities of TSH, LH, and FSH?
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The BETA subunit
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What is ACTH related to?
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MSH, B-lipotropin, and B-endorphin
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From what precursor are ACTH, MSH, B-lipotropin, and B-endorphin all derived?
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POMC - proopiomelanocortin
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Why don't humans really make much MSH?
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Because it's made in the INTERMEDIARY LOBE which is rudimentary in humans.
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What is the MOST important hormone for growth to adult size?
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Growth hormone!
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To what hormone is GH homologous?
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Prolactin
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How is GH released from the pituitary?
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Pulsatile
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What are 5 things that INHIBIT growth hormone release?
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SHOPS
-Somatostatin -Hyperglycemia -Obesity -Pregnancy -Somatomedins |
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What are 6 things that INCREASE GH secretion?
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-Puberty hormones
-Exercise -Sleep -Stress -Starvation -Hypoglycemia |
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How does the HYPOTHALAMUS regulate GH release?
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-GHrH is stimulatory
-SST is inhibitory |
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What happens when GH hits its target receptors?
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Somatomedins get made (IGF1)
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What do somatomedins do with regard to GH release?
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Inhibit it
-directly on the pituitary -indirectly by stimulating SST release from hypothal |
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Are SST and somatomedins the only things that inhibit GH release?
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No, GHRH inhibits ITS own release, and GH inhibits its on release too.
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How does GH inhibit its own release?
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By stimulating SST from the hypothalamus
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What is the target of GH? What is its effect there?
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LIVER - IGF1 release
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Does GH exert is effects only through IGF1?
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No it also has its own direct effects
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What are the direct effects of Growth hormone in general?
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Diabetogenic - it acts like lack of insulin
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What are the 4 direct effects of GH?
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1. Decreased cell glucose uptake
2. Increased lipolysis 3. Increased protein synth to increase lean body mass 4. Stimulate Liver IGF1 release |
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What are the 3 main actions of IGF-1?
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-Increased LINEAR growth
-Increased lean body mass -Increased ORGAN size |
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What is the increased linear growth stimulated by GH/IGF1 responsible for?
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The Pubertal GROWTH SPURT!
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What will lack of GH in children result in? (4 changes)
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Short, Fat, Fail to grow, Late puberty
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What can cause GH deficiency?
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Any step - GHRH lack, GH lack, GH receptor lack, liver fails to produce IGF1
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What is GH excess in childhood? Adult?
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Child - Gigantism
Adult - Acromegaly |
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What is the TREATMENT for GH excess?
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Octreotide - SST analog
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So what are 2 things Octreotide is used for treating?
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-Gigantism/Acromegaly
-Carcinoid tumor oversecreting GI hormones |
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What is the major hormone responsible for Lactogenesis?
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Prolactin
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What helps Prl with breast development?
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Estrogen
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What is Prolactin structurally homologous to? How do we remember this?
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GH - both made/secreted by Acidophils
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Where is Prl made and released from?
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Ant pit
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How is Prolactin release controlled by the Hypothal?
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-Tonically inhibited by Dopamine from hypothal
-TRH can increase Prl secretion |
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How is Prl secretion inhibited in addition to Dopamine's tonic inhibition?
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By NFB - Prl increases Dopamine secretion from hypothal
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What are the 4 effects of Prolactin?
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1. Stimulates milk production
2. Stim breast development w/ Estrogen 3. Inhibits ovulation 4. Inhibits spermatogenesis |
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How does Prolactin inhibit ovulation/spermatogenesis?
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By inhibiting the synthesis and release of GnRH from hypothal!
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So is Dopamine good for ovulation and spermatogenesis?
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YES
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What is a dopamine analog?
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Bromocriptine
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What will Prolactin deficiency cause?
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Failure to lactate
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What can cause Prolactin deficiency?
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Destruction of the pituitary
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What can cause Prolactin EXCESS?
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Hypothalamic destruction or Pituitary adenomas
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Why would hypothalamic destruction cause Prolactin excess?
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Failure to secrete dopamine, loss of inhibition.
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What will Prolactin excess do in females?
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-Galactorrhea (too much milk)
-Anovulation/Amenorrhea |
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What are the 2 post pit hormones?
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ADH/Oxytocin
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In what nucleus is ADH made?
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Supraoptic in hypothal
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What stimulates ADH release?
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-Increased serum OSMOLARITY
-Decreased blood VOLUME -Smoking/hypoglycemia -Pain/opiates NAUSEA |
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What inhibits ADH release?
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Opposites - high bl vol, low osm
ALCOHOL ANP, a-adrenergics |
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What are the 2 ACTIONS of ADH?
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1. Water reabsorption
2. Vasoconstriction! |
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How does ADH mediate its effects
-increased water reabs -vasoconstriction (receptor/ what signal transducer) |
Water - V2 receptor; cAMP
Vaso - V1 receptor; IP3 |
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What nucleus is Oxytocin made in?
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PARAVENTRICULAR nuclei
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What is the main action of oxytocin?
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Milk Ejection
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What is the major stimulus for oxytocin to stimulate milk ejection?
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Suckling
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What effects does Oxytocin have OTHER than just stimulating milk ejection?
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Parturition
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So what do we give to induce labor and reduce post-partum bleeding?
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Pitocin
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