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75 Cards in this Set
- Front
- Back
What is the major anabolic hormone?
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insulin
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What are counter-insulin hormones?
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epi, norepi, cortisol, GH, somatostatin, TH
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proglucagon is synthesized at what sites in the body? What other hormones does this gene contain?
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1) pancreas and L-cells of intestine
2) GLP1 and GLP2 |
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What is the half life of glucagon?
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3-6 minutes it is removed by liver and kidney
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What is the main target of glucagon?
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liver
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What is glucagons action on insulin?
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it increases insulin release but insulin suppresses glucagon
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Where in the body is somatostatin produced?
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D cells of pancreas, gastric and duodenal mucosa, hypothalmus
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What is tolbutamide?
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a sulfonylurea that increases insulin release
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What molecules increase somatostatin release? what hormones increase its release?
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1) glucose, arginine, leucine
2) glucagon, VIP, CCK |
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What pathway does somatostatin activate when it binds cells?
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G proteins and inhibits them decreasing cAMP and preventing PKA activation
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What hormones does somatostatin inhibit?
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GH, TSH, insulin, glucagon, TRH
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What effect does somatostatin have on gastric emptying?
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delays it, decreases acid secretion, and pancreatic enzyme release
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what is the half life of somatostatin?
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3 min
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What drug is an analog of somatostatin?
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octreotide with a long half life
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What is the half life of HGH?
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20-50 min
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What is a GH antagonist?
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pegvisomant
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To determine if someone has a GH tumor you would give them 100g of glucose. What should you see?
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a decrease in GH to less than 2ng/mL if it is not a tumor
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what is ornithine decarboxylase? What is GH effect on it?
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1) regulates cell proliferation
2) GH increases it |
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GH acts on what type of receptor? what proteins are stimulated when GH binds adipose cells?
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1) a tyrosine kinase
2) increased lipolysis, inhibition of LPL, increased hormone sensitive lipase, decreased glucose transport, decreased lipogenesis |
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Where is GHRH produced?
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arucuate nucleus
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What is IGF-1 effect on GH?
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negative feedback to somatotrope
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what molecules stimulate GH release?
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hypoglycemia, arginine,
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during prolonged fasting what hormone in particular increases lipolysis?
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GH spares glucose and protein
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increased amino acids have what effect on GH?
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increases its release
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what secondary condition develops with a GH tumor?
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diabetes
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What effect does estrogen have on GH? What about K+? Renal failure? progesterone?
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1) increases
2) increases 3) increases 4) decreases |
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Someone taking an alpha antagonist will have high or low GH? What about a beta agonist
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low
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Obesity has what effect on GH production?
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decreases it
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dopamine agonists increase or decrease GH release?
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increase
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is ketogenesis increased or decreased by GH?
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increased
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What effect does GH have on glycogen synthesis? what about gluconeogenesis?
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increases both
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IGF-1 is also known as?
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somatocedin C
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IGF-II is also known as?
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somatocedin A
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What do IGF-1 and insulin have in common structurally?
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they both contain the C peptide domain
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What type of receptor does IGF1 activate?
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tyrosine kinase
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what is different about IGF1 and IGF2 release?
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IGF2 is independent of GH
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what is the precursor to all catacholamines?
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tyrosine
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What have high levels of IGF1 been linked to?
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breast prostate, colon and lung cancer
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what effect does hypoxia have of catacholamine release?
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increases their release
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What are the metabolites looked for in someone with a pheochromocytoma?
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metanephrines and vanilylmandelic acid (VMA)
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where in the CNS are the adrenergic nuclei?
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hypothalamus
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Do catecholamines have a high or low affinity for receptors?
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low so that their effects are short lived
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Where is CRH released from?
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paraventricular nuclei
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Where in the adrenal cortex does ACTH act?
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zona fasciculata and reticulosa
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cushings disease is what? cushings syndrome is what?
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1) pituitary tumor
2) adrenocortical tumor |
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What is the effect of cortisol on fat, glucose and protein?
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increased lipolysis, decreased glucose uptake, proteolysis of skin, lymphoid cells and muscle
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What effect does cortisol have on phosphoenolpyruvate carboxykinase?
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increases it to increase gluconeogenesis
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cortisol has a catabolic effect on elastin. What results?
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sagging wrinkling skin and increased fragility of capillaries
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What causes plethora in people with cushings?
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thinning of facial skin
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What is the rate of iodide transport dependent on ?
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concentration of iodide in the thyroid cell
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Where is iodinium ion made?
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at the apical border of thyroid cell by thyroid peroxidase
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T4 is made up of what constituents?
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2 tyrosines, 4 iodine molecules
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In thyroglobulin what is the normal ratio of T4 to T3?
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13:1
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Is T3 or T4 the biologically active form?
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T3
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What is unique about the thyroid gland and its storage ability?
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it has a large storage capacity of amino acids linked to thyroglobulin in the colloid space
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what is the half of T4? T3?
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1) 7 days
2) 1 day |
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How do T4 and T3 travel in blood?
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bound to thyroid-binding globulin and 0.03% T4 is unbound and 0.3% T3 is unbound
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T4 and T3 are stored in vesicles in cells. What happens when TSH stimulates cells?
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causes lysosome to fuse with vesicle and degrade thyroglobulin to release T4 and T3 in 10:1 ratio
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TSH follows a circadian pattern. What is it?
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surge in late afternoon and peaks before sleep. Does have a pulsatile pattern though where it is released every 2-6 hours
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what intracellular signaling molecules are increased when TSH binds?
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cAMP, DAG and Ca2+
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What inhibits TSH and TRH release?
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T3 and at high levels it inhibits TRH
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What is the effect of excess T3 on muscle and amino acids? What about normally?
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1) breaks down muscle and sends amino acids to liver
2) increases glucose uptake, stimulates protein synthesis, increases muscle growth, but also increases glycolysis by sensitizing cells to epinephrine |
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What are the effects of T3 on the liver?
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1) increase glycolysis
2) increase cholesterol syn 3) increase production of bile salts 4) increase production of TAGs |
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How does T3 effect adipocytes? What happens if insulin and glucose are high?
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1) sensitizes adipose cells to epinephrine action leading to increased lipolysis (indirectly effects)
2) increased glucose with insulin can be converted to glycerol 3-phosphate which will promote lipogenesis |
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How does T3 effect glucose metabolism in liver?
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increases gluconeogenesis indirectly by sensitizing cells to epinephrine
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How would insulin be effected if T3 were absent?
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insulin release would be depressed because T3 increases sensitivity of beta cells to glucose
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How does T3 participate in "shivering" response to cold?
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sensitizes sympathetics which increases NE release and increases heat release by making cells more permeable to Na therefore increasing activity of Na/K atpase which breaks down ATP and releases heat
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What occurs in Refetoff disorder? What is the obvious physical exam finding?
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1) mutation in T3 receptor which causes symptoms of hypothyroidism
2) goiter occurs because T3 and TSH levels are very high |
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What happens to insulin clearance when someone has hyperthyroidism?
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it increases
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What is metathyroid diabetes mellitus
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glucose intolerance that results with hyperthyroid because insulin is degraded quicker than normal
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Where is ghrelin made and what does it do?
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1) CNS, stomach, intestine
2) stimulates GH release during fasting |
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Where is GLP-1 made and what does it do?
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1) L cells in ileum, colon and CNS
2) a. inhibits glucagon and increases insulin b. acts as an incretin to increase sensitivity to glucose in beta cells |
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Where is VIP made and what does it do? What causes its release?
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1) widely expressed in PNS and CNS
2) regulate insulin and glucagon release 3) mechanical stim of gut and activation of PNS and CNS |
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Where is motlin produced? what does it do and when is it released?
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1) M cell in duodenum
2) induces phase III contractions in stomach, increases gastric acid and pancreatic secretion, gallbladder contraction 3) duodenal alkalinization, gastric distention, suppressed by nutrients in duodenum |
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Where is GIP produced? What does it do? What causes its release?
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1) K cells of duodenum and jejunum
2) increases insulin (incretin), regulates glucose and lipid metabolism 3) increased by food, especially long chain fatty acids |