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63 Cards in this Set
- Front
- Back
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What are the 4 types of classical hormones?
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-Tyrosine derivatives
-Steroids -Peptides -Proteins |
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What makes peptides different from proteins?
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Peptides have <20 AA
Proteins have >20 AA |
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What are the 5 Tyrosine derivative hormones?
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1. Epinephrine
2. Norepinephrine 3. Dopamine 4. Triiodothyronine 5. Thyroxine |
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What are the 6 Steroid hormones?
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PETCAV
Progesterone Estradiol Testosterone Cortisol Aldosterone Vitamin D |
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What are the 8 Peptide hormones?
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VOMTGAGs
Vasopressin (ADH) Oxytocin Melanocyte-stimulating hormone Thyrotropin releasing hormone Gonadotropin releasing hormone Angiotensin Gastrin Somatostatin |
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What are the protein hormones?
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Insulin, Glucagon, ACTH, TSH, FSH, LH, GH, Prl, CRH, GHRH, PTH, CCK, Secretin,
Chorionic gonadotropin, |
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What is an Endocrine substance?
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A Substance released by ductless glands and transported via the blood to exert its effect on a target tissue other than that from whence it came.
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What is a Neuroendocrine substance?
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One that is released from nerves
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What is a Paracrine substance?
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One that acts on a different cell type than the one that released it, but in the same tissue.
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What is an Autocrine substance?
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One that is released by a cell and acts on that same cell.
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What does the chemical nature of a hormone or endocrine substance determine?
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Specificity - what receptor the substance will bind.
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What hormones have the highest percent of protein binding?
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Thyroxine T4 and Triiodothyronine T3
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What hormones has the longest half life and lowest metabolic clearance? What are intermediate?
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Highest protein bound:
T4 > T3 (both almost 100%) Intermediates: Cortisol .94 Testosterone .89 Aldosterone .15 |
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What does long half life and low metabolic clearance indicate?
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That the substance is highly bound by plasma proteins, hence protected from metabolism or clearance.
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What 3 hormones are bound to nil protein and degraded quickly?
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-TSH
-Growth hormone -Insulin (all proteins) |
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Why do we care how much hormone is free vs protein-bound?
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Because it's the free hormone that is biologically active.
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If a hormone is not ever bound by plasma proteins what determines its rate of metabolism?
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The size - determines how long it takes to chop it up.
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Which of the protein hormones is biggest hence has longest 1/2 life?
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Thyrotropin = 28,000 mw
Growth hormone = 22,000 mw Insulin = 6000 mw |
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3 types of endocrine rhythms:
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-Circadian
-Ultraradian -Stimulus-induced |
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What is the classic example of a circadian hormone? When does it peak? Trough?
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Cortisol
-Peaks in morning (8am) -Troughs at night (11-12pm) |
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What is the classic example of an ultraradian hormone? When does it spike?
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Gonadotropin Releasing hormone
-Spikes every 90 minutes |
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What is the classic example of a stimulus-induced hormone?
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Prolactin - stimulated by suckling.
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Where is Glucagon made?
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In the alpha cells of the pancreas
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What stimulates/inhibits Glucagon release from alpha cells?
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Glucose inhibits Glucagon release
Low glucose stimulates it |
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What does Glucagon do?
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Acts on the liver to cause gluconeogenesis
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What is the classic example of a parallel negative feedback loop?
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Glucose made by gluconeogenesis will stim Insulin from Bcells & inhibit Glucagon from a-cells, so the liver will stop making more glucose.
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What is the first thing necessary for a hormone to be able to act on its target?
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The target must express the correct receptor so it can form a Hormone-Receptor Complex.
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What happens in general when a hormone binds its receptor?
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It activates a cascade so that even small amounts of the hormone will have large effects.
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What are 3 locations that a hormone receptor can be?
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1. In or on the cell surface
2. In the cell cytoplasm 3. In the cell nucleus |
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Which hormones generally bind cell surface receptors?
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-Proteins
-Peptides -Catecholamines |
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Which hormones generally bind cell cytoplasm receptors?
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Steroid hormones
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Which hormones generally bind nuclear receptors?
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Thyroid hormones
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What types of endocrine substances act on Ion Channel-Linked Receptors?
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Neurotransmitters like ACh and Norepi
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To what receptor type do the majority of hormones bind?
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G-protein coupled receptors
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What is the business end of the G-protein coupled receptor?
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The alpha subunit which is GTP bound in its active form.
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What is the Leptin receptor a prime example of?
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Enzyme-linked Receptors
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What are the 2 components involved in leptin receptor binding?
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1. Fast physiological effects via activation of an enzyme cascade
2. Slower effects via activation of STAT proteins. |
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What is a STAT protein?
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Signal Transducer and Activator of Transcription
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What type of structure is the leptin receptor?
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A homodimer
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What is the signal transduction protein that is bound to the intracellular side of the leptin receptor?
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Jak2
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What happens when leptin binds its receptor?
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1. Phosphorylates Jak2
2. Jak2-Pi phosphorylates STAT3 3. STAT3-Pi activates protein transcription |
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What cells secrete leptin?
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Adipocytes
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What are the important physiological effects of leptin?
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-Regulation of appetite
-Energy balance |
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What receptor family is the leptin receptor a member of?
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The cytokine receptors
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What hormones act by using intracellular or nuclear receptors?
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Steroids and Thyroid hormones
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How do intracellular/nuclear receptors work?
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1. Hormone binds receptor
2. Hormone-receptor complex binds HRE - hormone response element 3. Exerts its effect |
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What is an HRE?
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A DNA promotor region
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How can hormones alter genetic activity via HREs?
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By either activating or inhibiting gene txpn, trnsltn, and protein synthesis
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What is the major difference in the result of hormones binding enzyme-linked or cell-surface receptors vs intracellular & intranuclear receptors?
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TIMING - it takes a lot longer to see the results of gene manipulation.
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What is the predominantly important 2nd msgr to know?
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cAMP
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How is cAMP formed?
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By a hormone binding its cell surface receptor, activating g-protein a-subunit, which activates Adenylyl Cyclase which converts ATP -> cAMP
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What are 2 other important 2nd msgrs?
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-Calcium/Calmodulin
-PLC breakdown products |
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What activates phospholipase C?
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A g-protein activated by hormone binding its cell receptor
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What does PLC do?
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Breaks down PIP2 into DAG + IP3
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What does DAG do?
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Converts inactive Protein Kinase C into Active PKC
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What does protein kinase C do?
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Phosphorylates proteins to activate them
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What does IP3 do?
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Makes the ER release Calcium
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What is the classic hormone that acts via PLC/PIP2->IP3+DAG?
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Angiotensin
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What is the classic example of a hormone that acts via G-protein coupled generation of a cAMP second messenger?
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ACTH and catecholamines
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What is the most potent form of Thyroid hormone?
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T3 - triiodothyronine
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What is the form of thyroid hormone that is released in large amounts?
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T4 - thyroxine
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What is the direct effect of thyroid hormones on their target cells?
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To increase transcription of specific genes in the nucleus
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What is the general nature of the protein products of transcription activated by thyroid hormones?
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They enhance intracellular metabolic activity in virtually all cells of the body
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