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22 Cards in this Set

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cells of the pituitary gland secreting which hormones are acidophils? basophils?
acidophils - GH, prolactin

basophils - rest
FLAT PiG
(FSH, LH, ACTH, TSH, ProlacIn, GH)
FSH shares a subunit with other hormones, which hormones? which subunit is shared and which is unique?
TSH, LH, FSH, hCG all share alpha subunit

beta subunit determines hormone specificity

*remember this because pregnancy test is BETA-hCG
what stimulates insulin release from beta cells? what inhibits it?
epinephrine/glucagon --> increased cAMP --> increased intracellular Ca++ --> inuslin released

High glucose (from GLUT2) --> high ATP/ADP ratio --> increased activity of ATP sensitive K+ channel --> depolarization --> increased Ca++ influx --> insulin release

*inhibited by alpha-2 receptor agonization, or by low ATP/ADP
varies GLUT transporters, activities, and tissues?
GLUT1 - insulin independent; brain, RBCs

GLUT2 - bidirectional, insulin independent; beta-islet cels, liver, kidney, small intestine

GLUT4 - insulin RESPONSIVE, adipose tissue, skeletal mm

Qbank:
GLUT3 - placenta, brain, kidney
GLUT5 - spermatocytes, GI tract (fructose transport)
which tissues are insulin dependent?
adipose tissue, skeletal mm
GLUT4
What is the effect of glucagon? how is it stimulated? inhibited?
glycogenolysis & gluconeogenesis
lipolysis & ketone production

stimulated by hypoglycemia

inhibited by insulin, hyperglycemia, & somatostatin
Hypothalamic-pituitary hormone regulation:

TRH -->
Dopamine -->
CRH -->
GHRH -->
Somatostatin -->
GnRH -->
Prolactin -->
TRH --> + TSH, prolactin
Dopamine --> - prolactin
CRH --> + ACTH
GHRH --> + GH
Somatostatin --> - GH, TSH
GnRH --> + LH, FSH
Prolactin --> - GnRH
what is the fxn of prolactin? how is it stimulated? inhibited?
prolactin stimulates milk production; inhibits ovulation (& spermatogenesis) by inhibiting GnRH

Stimulated by TRH (or disinhibition of dopamine)

Tonically inhibited by dopamine; feeds back and inhibits self


Dopamine agonists (bromocriptine) inhibit prolactin secretion - tx prolactinoma
Dopamine antagonists (antipsychotics) & estrogens (OCP, pregnancy) stimulate prolactin secretion
what is the fxn of GH? how is it regulated?
stimulates linear growth & mm (thru somatomedin secretion)
increases insulin resistance (diabetogenic)

GHRH stimulates GH release; pulsatile
secretion increases during exercise & sleep

secretion is inhibited by glucose & somatostatin
what are the fxns of cortisol? how does it circulate?
binds to CBG (corticosteroid-binding globulin)

Cortisol is BBIIG
1.) maintains Blood pressure (upregulates alpha-1 receptors)
2.) decreases Bone formation
3.) anti-Inflammatory/Immunosuppressive
---inhibits production of leukotrienes & prostaglandins
--inhibites leukocyte adhesion --> neutrophilia
--blocks histamine release from mast cells
--reduces eosinophils
--blocks IL-2 production
4.) increases Insulin resistance (diabetogenic)
5.) increases Gluconeogenesis, lipolysis, proteolysis
where is PTH produced? what are its functions?
produced by Chief cells of the parathyroid; increases Ca+ & decreases PO4

1.) increase bone resorption of Ca++ & PO4
2.) increase renal absorption of Ca++ (distal tubule)
3.) decrease renal absorption of phosphate
4.) increase kidney activity of 1alpha-hydroxylase, increasing 1,25-OH vitamin D (calcitriol)
how does PTH increase bone resorption?
stimulates osteoblasts, which secrete M-CSF & RANK-L, which stimulate osteoclasts
how is PTH regulated?
PTH secretion is increased w/low free Ca++ and Mg++

low Mg++ caused by: diarrhea, aminoglycosides, diuretics, alcohol abuse
what does vitamin D deficiency cause in adults? kids?
adults - osteomalacia
kids - rickets
how is Vitamin D production stimulated? inhibited?
1alpha hydroxylase is stimulated by - high PTH, low Ca and phosphate, produces more active vitamin D

1,25-OH vitamin D feedback inhibits its own production
where is calcitonin produced? what does it do?
parafollicular cells (C cells) of thyroid

it decreases bone resorption of calcium; it is secrted in response to high Ca

(in medullary carcinoma might see high primary calcitonin levels --> hypocalcemia w/trousseaus and chvotsek's sign)
what does increased/decreased SHBG do?
in men, increased SHBG --> lowers free testosterone --> gynecomastia

in women, decreased SHBG --> raises free testosterone --> hirsuitism
which thyroid hormone is the active form? what are the funcitons?
T3 is active; majority is formed by peripheral conversion (5' deiodinase); binds to steroid transcription factors in the nucleus

Fxns - 4B's, Brain, Bone, Beta-adre, BMR

1.) Bone growth (synergism w/GH)
2.) CNS maturation
3.) increased beta-receptors in heart
4.) increased basal metabolic rate (via increased Na/K ATPase activity)
5.) increase glycogenolysis, gluconeogenesis, lipolysis
how is thyroid hormone regulated?
TRH stimulates TSH, stimulating follicular cells

negative feedback of T3 to anterior pituitary decreases sensitivity to TRH
what is Wolff-Chaikoff effect?
excess iodine inhibits thyroid peroxidase, which prevents organification

lasts ~10 days before "escape phenomenon"
how does thyroid hormone circulate? what effects this?
bound to TBG

TBG decreases w/hepatic failure
TBG increases w/pregnancy or OCP use
what enzymes are important for thyroid hormone to be active? how are the manipulated pharmacologically?
5'-deiodinase converts T4 to T3 in the periphery
Peroxidase is responsible for oxidation & organification of iodide, and coupling of MIT & DIT

Propylthiouracil inhibits peroxidase & 5'-deiodinase
Methimazole inhibits peroxidase