Term
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Definition
makes mineralocorticoids
lacks 17alpha hydroxylase (progesterone to 17-α-hydroxyprogesterone)
but has 21-alpha-hydroxylase used to make DOC (deoxycorticosterone) and aldosterone
Only uses delta 4 pathway |
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Term
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Definition
primarily targets the kidney, and specifically the principal cells (P cells) of the distal tubule and collecting duct, to upregulate basolateral Na+-K+ ATPases, increase sodium, and thus chloride and water, reabsorption
aldosterone increases sodium reabsorption by increasing the opening frequency and duration of the existing sodium channels,
increasing sodium uptake by the P cells,
and increasing the activity of the basolateral Na+-K+ ATPases.
As a result, aldosterone causes increased potassium excretion.
Among its long-term effects, aldosterone increases the synthesis and exocytosis of more sodium channels in the apical membrane of the P cell. Aldosterone also causes increased H+ excretion and the acidification of the urine by indirectly increasing the activity of the apical H+-K+ antiporter on intercalated cells
released through RAAS, high extracellular K+, and increased ACTH |
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Term
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Definition
| hypertension and hypokalemia |
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Term
| 11-β-hydroxysteroid dehydrogenase (11-β-HSD) |
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Definition
Type 2
found in kidney
oxidizes cortisol by removing a hydrogen atom and producing cortisone
Type 1
found in liver
cortisone to cortisol |
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Term
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Definition
inhibits PLA2 (decrease prostaglandins)
stimulates catecholamine synthesis and upregulates beta 1 adrenergic receptors
stimulates PNMT activity |
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Term
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Definition
decreases ANP secretion
increases ADH secretion
increases aldostersone secretion and vasoconstriction
activates sympathetic system |
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Term
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Definition
CNS: euphoria and polyphagia
decrease fibroblast activity and increase osteoporosis risk
Cushings Syndrome
fat redistribution
polyphagia
hypertenshion
mood changes
hypernatriemia
hypokalemia
in 2ndary and 3tiary:
increased ACTH means increased androgens, decreased gonadotropin secretion.
cortisol will also decrease sensitivity to GnRH of the gonadotrops |
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Term
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Definition
addison's/adrenal insufficiency
low HP
fatigue
weight loss
tan.
if primary, then high ACTH will cause the tan |
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Term
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Definition
calcitrol: vitamin D; favors Pi reabsorbtion, increases calbindin activity(calcium from intenstine to circulation)
PTH: Gs upregulate RANK-L, to downregulate osteoprotegerin, to increase mCSF, and to increase the secretion of interleukin-6 (IL-6), which further stimulates osteoclast formation, decreases OPG synthesis, and increases RANK-L synthesis
estrogen/androgens
Interleukin 1/6/11 helf synthesize rankL |
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Term
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Definition
| make hydroxyapatite in osteoblasts |
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Term
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Definition
secrete collagen to osteoid
stimulate osteoclasts with mCSF, and RANKL, inhibit them with OPG
transports materials and senses load on bone |
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Term
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Definition
receptors for calcitonin, RANK, and cFMS
integrins help it bind to bone
apical membrane: H/K ATPase
H pumps
Cl channels
basolateral membrane: Na K ATPase
Cl/HCOs exchanger
cytosol: carbonic anhydrase
stimulated by: osteoblasts under influence of PTH calcitrol IL1,6,11
inhibition by: OPG androgens/estrogen inhibit IL6 |
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Term
| Parathyroid hormone secretion |
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Definition
| parathyroid endocrine cells contain a calcium sensing receptor (CaSR), which has an intracellular portion linked to the Gq pathway |
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Term
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Definition
. In the bone, PTH binds to its receptors on the osteoblast to upregulate RANK-L, to downregulate osteoprotegerin, to increase mCSF, and to increase the secretion of interleukin-6 (IL-6), which further stimulates osteoclast formation, decreases OPG synthesis, and increases RANK-L synthesis
distal tubule and collecting duct of the kidney, PTH binds to its basolateral receptors to increase calcium reabsorption by upregulating Ca+2 pumps, Na+-Ca+2 antiporters, and calcium leak channels
inhibits Pi reuptake
proximal tubule: increased activity of 25-(OH)D3 –α-hydroxylase, an enzyme which hydroxylates the precursor of calcitriol |
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Term
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Definition
7-dehydrocholesterol, fatty acid precursor in the epidermis, absorbs UV radiation (270-310 nm), then turns to Cholecalciferol
Then
hydroxylated in the liver forming 25-(OH)D3, which then is shuttled to the proximal tubule to become activated via a second hydroxylation
In the absence of PTH, calcitriol will not be formed. Also, the high levels of prolactin found during pregnancy also stimulate 25-(OH)D3 –α-hydroxylase and produce active calcitriol |
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Term
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Definition
| In addition to its effects, and distinct from PTH, calcitriol stimulates the synthesis of calbindin, which is a calcium binding protein found on the apical membrane of the intestinal epithelial cells. Calbindin is a calcium shuttle in that it binds calcium from the intestinal lumen and shuttles the calcium across the intestinal cell cytosol to the basolateral membrane and releases the calcium into the circulatory system. Thus, adequate plasma calcitriol levels are essential for efficient dietary calcium uptake |
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Term
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Definition
hormone replacement therapy
Selective Estrogen Receptor Modulators
bisphosphonates (bone glue) |
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