Quiz 2 Hormones Flashcards
Types of Hormones
Steroid, Protein, and Amines
Steroid Hormones: synthesized by/from, transport
By: Adrenal glands, gonads, placenta
From: Cholesterol, lipid-soluble, made as needed rather than stored
Transport: Need a carrier protein to circulate
Clinically Significant Steroid Hormones
Cortisol, Aldosterone, testosterone, estrogen, and progesterone
Mechanism of Action: steroid hormones
Diffuse into cell and intercellular receptor, telling it to make new mRNAs
Controlled by negative feedback loop
Protein Hormones: synthesized by/from, transport
By: Anterior Pituitary, placenta, pancreas, parathyroid
From: Made and stored
Transport: do not need carrier protein, water-soluble
Clinically Significant Protein Hormones
Pituitary: FSH, LH (lutinizing), TSH, Growth Hormone, Prolactin
Placenta: HCG (Human chorionic gonadotropin)
Pancreas: Insulin, Glucagon
Parathyroid: PTH
*Those with acronyms all have the same Alpha chain but different Beta chains
Mechanism of Action: protein hormones
Attach to mem. receptor, stimulate cellular action
Feedback: change in hormone level or analyte
Amine Hormones: synthesized by/from, transport
By: Thyroid, adrenal
From: amino acids
Transport: Thyroids do, Adrenals do not
Clinically Significant Amine Hormones
Epinephrine, norepinephrine [Catecholamines]
Thyroxine (T4), triiodothyronine (T3)
Mechanism of Action: amine hormones
Adrenals: react with cell surface receptor
Thyroid: diffuse into cell
Feedback: activated by nervous system (adrenals)
TBG
Thyroxine binding globulin
CBG
Cortisol binding globulin
SHBG
Sex hormone binding globulin
Androgens
Hormones produced in adrenal cortex/gonads
androgens (testosterones), progesterone, estrogens
Hypothalamus/Pituitary/End Organ System
Hypothalamus makes releasing hormone that stimulates pituitary to release stimulating hormones that in turn cause an end organ to produce hormones or initiate a process
Primary Hyper/hypo conditions
End Organ problem
Secondary Hyper/hypo conditions
Pituitary problems
Tertiary Hyper/hypo conditions
Hypothalmic problem
Regulation of Hypothalamus/Pituitary/End Organ System
End organ product or process feeds back to Hypothalamus and Pituitary to stop hormone production
Thyroid Hormones
Stimulate metabolic processes for growth and development
T4 is converted to T3 in tissues, T4 concentration is higher
99.97% T4 is bound to TBG and TBPA, 0.03% is free
99.5% T3 is bound and 0.5% is free
Only the free portions are metabolically active
TBG and TBPA
Thyroxine Binding Globulin
Thyroxine Binding PreAlbumin
Primary Hyperthyroidism
Low TSH, High T4 and T3
Most commonly caused by Graves disease
Graves Disease
Autoimmune
Antibodies to TSH receptors push the thyroid to produce T3/T4 and suppress TSH
T3/T4 levels are normal or high, TSH is low
Primary Hypothyroidism
Low T3/T4 and high TSH
Causes: Congenital (cretinism), Myxedema (severe thyroid deficiency), Hashimoto’s Thyroiditis
Hashimoto’s Thyroiditis
Autoantibodies to Thyroid, low T3/T4 and high TSH
Thyroid Function Tests
TSH, Total thyroxine, Free T4, Direct T3
Hypothalamus/Pituitary/Thyroid System
Thyrotropin Releasing Hormone (TRH) -
Thyroid Stimulating Hormone (TSH) -
Thyroid -
T3/T4
Hypothalamus/Pituitary/Adrenal Cortex System
Corticotropin Releasing Hormone (CRH) -
Adrenocorticotropic Releasing Hormone (ATCH) -
Adrenal Cortex -
Cortisol, Aldosterone, Estrogens, Testosterone
Hypothalamus/Pituitary/Ovaries-Testes System
Gonadotropin Releasing Hormone (GnRH) - Leutinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) - Ovaries or Testes - Ovulation or Spermatogenesis
Adrenal Cortex Hormones
Produces 3 kinds of Steroid hormones: Mineralcorticoids (Aldosterone) Glucocorticoids (Cortisol) Sex hormones (Androgens/Estrogens) Regulated by cortisol feedback to hypothalamus/pituitary
Aldosterone
Maintain BP, sodium reabsorption and potassium secretion
Regulated by Renin-angiotensin system
Renin-angiotensin System
Renin converts angiotensinogen to angiotensin I which is converted to angiotensin II that stimulates aldosterone production
Hyperaldosteronism
Conn’s Disease
Causes increased Na and lowered K with hypertension
Hypoaldosteronism
Addison’s Disease
Lowered Na, Cl, cortisol, hemoglobin, and urinary steroids
ACTH is increased if primary and decreased if secondary/tertiary
Cortisol
Causes increased Glucose through gluconeogenesis and decreases carbohydrate use
Inhibits protein synthesis
Immunosuppressive and anti-inflammatory
Cushing’s Syndrome
High cortisol
Seen in diabetes mellitus, with lowered plasma proteins and hypertension
Signs include Truncal obesity, facial hair, “buffalo hump” osteoporosis, and scant menses
Androgens
Secreted by testes, ovaries, and adrenals
17-ketosteroids: metabolites of androgens found by the Zimmerman reaction
Estrogens
Estradiol: secondary sexual characteristics
Estrone: metabolite of estradiol
Estriol: increases during fetal development, most steadily in third trimester
Cortisol Function Tests
Cortisol: Free or total in serum, plasma, or urine; has diurnal variation and is highest in the morning
- Dexamethasone suppression: suppresses cortisol production, if cortisol still high it indicates Cushing’s
Aldosterone Function Tests
Aldosterone levels increase while patient is in upright position
Renin Function Tests
Produced in kidneys, drawn from either renal vein
Renin Activity or Direct Renin Testing
Will be low in Conn’s
ACTH Function Testing
Distinguishes between primary and secondary hyperaldosteronism
Adrenal Medulla Hormones
Catecholamines (epinephrine, norepinephrine, dopamine)
Homovanillic acid is a metabolite of dopamine
Metanephrines and vanilylmandelic acid are metabolites of epinephrine
Produced by Chromaffin cells
Pheochromocytoma
Tumor of adrenal medulla causing hypertension
Neuroblastoma
Fatal tumor in children
Catecholamines Testing
Plasma or urine
Metanephrines in urine best screen for pheochromocytoma, VMA and HVA are tested for in urine
Serotonin
Vasoconstrictor in platelets, brain, and other tissue
Increased production in tumors of chromaffin cells of GI tract
Breakdown product 5-hydroxy-indole-acetic acid is measured in urine
Natriuretic Hormones
ANP, CNP, BNP (Brain)
Promote excretion of sodium and water by increasing GFR
BNP additionally in synthesized in the myocardial ventricles in response to volume overload (Congestive Heart Failure) to dilate vessels and promote water loss to reduce fluid amount
