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o this is something that really troubles me alot... swear!!! thanks ayash:)
 

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Hello forum members,

Just thought I would share these HY notes with you all.

Good Luck!
ARE you sure about thyroid and vitD receptors being inside nucleus? are not they in cytoplasm? just wondering! different sources different inputs
 

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ARE you sure about thyroid and vitD receptors being inside nucleus? are not they in cytoplasm? just wondering! different sources different inputs
ok i just read that thyroid hormones receptors are located in nucleus but still not sure about vit.D.
ANYONE? ANY IDEAS?
 

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ok i just read that thyroid hormones receptors are located in nucleus but still not sure about vit.D.
ANYONE? ANY IDEAS?
Vitamin D is fat soluble and therefore it must be able to slip through the cell membrane and nuclear membrane and exerts its action there.
 

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Vitamin D is fat soluble and therefore it must be able to slip through the cell membrane and nuclear membrane and exerts its action there.
Not necessary. we are talking about whether receptor is in cytoplasm or in nucleus. as you know steroid hormones -glucocorticoids, testosteron,..-are all lipid soluble but their receptor are located in cytoplasm. please correct me if i am missing something here.
 

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Not necessary. we are talking about whether receptor is in cytoplasm or in nucleus. as you know steroid hormones -glucocorticoids, testosteron,..-are all lipid soluble but their receptor are located in cytoplasm. please correct me if i am missing something here.
Steroid hormone receptors are located in the nucleus not in the cytoplasm.
When a substance is lipid soluble, there's no need for cell surface or cytoplasmic receptor as it can diffuse in.
To reaffirm for you the location of Vitamin D receptor please read this Wikipedia article http://en.wikipedia.org/wiki/Calcitriol_receptor
 

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Steroid hormone receptors are located in the nucleus not in the cytoplasm.
When a substance is lipid soluble, there's no need for cell surface or cytoplasmic receptor as it can diffuse in.
To reaffirm for you the location of Vitamin D receptor please read this Wikipedia article http://en.wikipedia.org/wiki/Calcitriol_receptor
you can not always trust wikipedia..

i am not sure about vitD RECEPTOR but i am pretty sure steroid receptors are in cytoplasmn when hormone binds receptor then H-R complex is dislocated into nucleus and seat on HRE.
 

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Trust me on this one

I am pretty sure steroid receptors are in cytoplasmn when hormone binds receptor then H-R complex is dislocated into nucleus and seat on HRE.
What you said, means that the ultimate receptor for steroids is in the nucleus!
The GRE (Glucocorticoid response element) is in the DNA. This is the ultimate receptor for all steroid hormones.
The HRE complex is a temporary messenger, the ultimate receptor is in the nucleas. This is well known and is not debatable. In fact, it's a common question in the USMLE where they ask you about the location of steroid hormone receptor and you have to choose the nucleus.
If you don't trust Wikipedia Here's a diagram from Cell and Molecular Biology: Concepts and Experiments by Gerald Karp


And for vitamin D, here's a diagram from Vitamin D: Physiology, Molecular Biology, and Clinical Applications (Nutrition and Health)
 

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I wonder how the question would be phrased?

Whether cytoplasmic (like cortisol in Hokolesqua's first picture) or nuclear (like Vit D in the second picture), the principle still applies, as both regions are separated from the circulation by a lipid membrane. A hydrophilic molecule would have a receptor on the cell membrane; a lipophilic one past the cell membrane. So Hana's question about cytoplasm v. nucleus was valid. But, as Hokolesqua said, there is no second messenger. I'm interested to know how the question would be phrased, in the case of, say cortisol. It meets the GR in the cytoplasm and travels with two of them into the nucleus, where the complex binds to the response element. Hmm...

Looks like Vit D was answered anyway!
 

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plz clarify!

The attached PDF states nuclear receptor for T3/T4 & Vit A & Vit D :(
but FA 2011 states Vit D as cytosolic
can anyone tell which one is correct? :toosad:
 

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The attached pdf states
nuclear receptor for T3/T4 & VitA & Vit D :(
but FA 2011 states Vit D as cytosolic
can anyone tell which one is correct? :toosad:
that is why i asked about vitD, different sources different info..
huuuuum, may be it is just not high yeild? whether in nucleus or cytoplasm.
 

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@hokolesqua;
if cortisol does not seat on it is receptor at first place in cytoplasm ,there is no way it can access into nucleus.
the target is nucleus-gene expression modification-but receptor cytoplasm
and i just read this q on UW yesterday it clearly said ;MOST steroid receptors are cytoplasmic " .
i would choose cytoplasm in exam :)
btw,thanks for nice photos you posted :))
 
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