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Discussion Starter · #1 ·
Hi guys!
Can anyone explain me how cortisol decreases bone formation? does it increase the activity of osteoclasts?
 

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due to osteoporosis

Hypercortisolism is the Secondary cause of osteoporosis (which is most common metabolic abnormality of bone)
PATHOGENESIS:
Loss of both organic bone matrix and minerals
(1) Decreased bone mass and density
• Radiograph shows osteopenia (washed out appearance).
(2) Decreased thickness of cortical and trabecular bone :)
Classification
(1) Primary
(a) MosT common type (80% women. 60% men)
(b) Idiopathic type in children and young adults
(c) Postmenopausal type (most common)
(d) Senile type in men andwomen
(2) Secondary
(a) Underlying disease (e.g., hypercortisolism)
(b) Drugs (e.g.. heparin)
(e) Hypogonadism (e.g.. hypopituitarism)
(d) Malnutrition (e.g.. anorexia nervosa)
(c) Space travel (Lack of gravity reduces bone stress).

Hope this helps :D
 

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Hi guys! Can anyone explain me how cortisol decreases bone formation?does it increase the activity of osteoclasts?
Rather, it decreases number and activity of osteoblasts.

From Emedicine:
Endocrinologic conditions or medications that lead to bone loss (eg, glucocorticoids) can cause osteoporosis. Corticosteroids inhibit osteoblast function and enhance osteoblast apoptosis...
 

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Discussion Starter · #4 ·
Steroids decrease GI absorption of calcium,inhibit collagen synthesis by osteoblasts,decrease gonadotrophin releasing hormone leading to hypogonadism,and increase urinary loss of calcium.this is what I get from uworld question.I don't know the mechanism.
 

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cortisol effects

This is just a quick review I have of the effects of cortisol on body, some of which I think is helpful for step 1:
Cardiovascular System-->upregulates alpha 1--> hypertension
Collage- Reduce collagen synthesis- striae
Bone- inhibit osteoblastic activity
Intestines- reduce calcium reabsorption
Kidney- increase calcium release
Important for fetal lung maturation : surfactant
Increases lipogenesis- increasing truncal obesity
Causes insulin resistance and increases gluconeogensis
Inhibits Arachidonic acid breakdown-->specifically PLA2 enzyme leading to reduction on inflammatory response
Increases in ulceration and gastric acid production due to inhibition of prostaglandin PGI2--> protective agent for gastric ulceration.
 

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Hypercortisolism is the Secondary cause of osteoporosis (which is most common metabolic abnormality of bone)
PATHOGENESIS:
Loss of both organic bone matrix and minerals
(1) Decreased bone mass and density
• Radiograph shows osteopenia (washed out appearance).
(2) Decreased thickness of cortical and trabecular bone :)
Classification
(1) Primary
(a) MosT common type (80% women. 60% men)
(b) Idiopathic type in children and young adults
(c) Postmenopausal type (most common)
(d) Senile type in men andwomen
(2) Secondary
(a) Underlying disease (e.g., hypercortisolism)
(b) Drugs (e.g.. heparin)
(e) Hypogonadism (e.g.. hypopituitarism)
(d) Malnutrition (e.g.. anorexia nervosa)
(c) Space travel (Lack of gravity reduces bone stress).

Hope this helps :D
Doesn't really answer the question though...
 

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This is just a quick review I have of the effects of cortisol on body, some of which I think is helpful for step 1:
Cardiovascular System-->upregulates alpha 1--> hypertension
Collage- Reduce collagen synthesis- striae
Bone- inhibit osteoblastic activity
Intestines- reduce calcium reabsorption
Kidney- increase calcium release
Important for fetal lung maturation : surfactant
Increases lipogenesis- increasing truncal obesity
Causes insulin resistance and increases gluconeogensis
Inhibits Arachidonic acid breakdown-->specifically PLA2 enzyme leading to reduction on inflammatory response
Increases in ulceration and gastric acid production due to inhibition of prostaglandin PGI2--> protective agent for gastric ulceration.
Are you sure cortisol causes lipogenesis? i thought i causes LIPOLYSIS ?
 

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r u sure cortisol causes lipogenesis? i thought i causes LIPOLYSIS ?
Cortisol like ALL other stress hormones does cause lipolysis. It increases the fat i nthe body hence in cushing we see the buffalo hump.
other affects if cortisol are to block glucose uptake into tissues so therefore there is incrase glucose. and it will cause gluconeogenesis in the liver to incrase more glucose. remember body is stressed so it is not thinking about saving energy. And glucagon has a premissive action on cortisol.
Also high cortisol levels decrease the level of functioning osteoblast and according to Kaplan the osteoclastic activity is incrased.
 

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  1. Corticosteroids decrease calcium absorption from the gut.
  2. They also have direct anti-anabolic effects on bone.
  3. They also suppress GnRH which can lead to central hypogonadism which in turn can aggravate bone loss.
 

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Cortisol decreases the expression of Vitamin D receptor--an intranuclear cytoplasmic receptor--(~10% of all functional genes in the human body have a glucocorticoid receptor responsive element or GRE upstream of them). Dec.'d vitamin D receptor (A) will decrease absorbtion of Ca @ gut and @ kidney as well as decrease Ca deposition by osteoblasts (B) Dec.'d vitamin D will dis-inhibit PTH causing functional parathyroidism--> @osteoblasts this will dec. osteoblast proliferation and inc. RANKL expression will suppressing OPG secretion-->augmenting osteoclast activity. A and B lead to osteopenia (X-ray) and osteoporosis (clinical Dx).
 
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