plz answer this Q

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plz answer this Q

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14 Posts

nadiabarati

02/24/06 - 08:18 PM

47. Which of the following best describes an aspect of the mechanism of action of thyroid hormone?

A. Binding to receptors on mitochondria that directly alter phosphate:oxygen ratio (P/O)
B. Binding to receptors that directly modulate transcription of specific genes
C. Interaction with a G protein associated with the plasma membrane
D. Interaction with guanylyl cyclase without G-protein mediation
E. Interaction with a plasma membrane receptor on target cells
F. Participation by the second messenger cAMP

vinaysaini19
Forum Junior

Topics: 12
Posts: 61

02/25/06 - 12:41 AM

Its B because thyroid is a steroidal hormone which acts by increasing the transcription of genes and many of mithochondrial products are encoded by nucleus.

mazinger
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02/25/06 - 02:16 AM

Agree all liposoluble hormones bind to intracellular receptors.. Steroid hormones, thyroid hormones, Calcitriol..

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robin082006
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02/25/06 - 09:04 AM

yes B

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nadiabarati

02/25/06 - 01:22 PM

but I believe in D
I read somewhere about thyroid hormone receptor that is D raised eyebrow

doc179
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02/25/06 - 02:03 PM

kaplan pharma regarding types of receptors states abt thyroid ...the ans is B

mildus
Forum Guru

Topics: 19
Posts: 614

02/26/06 - 04:19 AM

It's B.
Hormones which receptors are associated with cGMP are:
1. ANP (also BNP and CNP)
2. NO

mildus
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02/26/06 - 04:21 AM

ANP's receptor is associated with membrane guanilat-cyclase, while NO's receptor is soluble guanilat-cyclase

Janka
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Topics: 28
Posts: 146

03/02/06 - 06:28 AM

B it is for sure.
the receptor is a dimer consisting of t4R and retinoateR and acts as a transcription factor.
by the way: hi everyone, i am a medical student from germany preparing to take usmle step1 in july. looking forward to exchange ideas and help.

mjl1717
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03/02/06 - 08:22 PM

#10

what about answer-f

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doc179
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03/02/06 - 08:29 PM

#11

steroids bind to intracellular receptors there are no second messengers involved

doc179
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03/02/06 - 08:31 PM

#12

thyroid hormones have receptors intracellularly

zzzz
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03/03/06 - 08:53 PM

#13

lipid soluble hormones diffuse through the cell membrane where they bind to their respective receptor inside the cell the receptor has dna binding domain usually zn finger and iteract with specific response elementin enhacer region with certain gene .lipid soluble hormones don't need second messanger mech.it is for water soluble hormones .B is right ans.

pearljam59
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03/20/06 - 01:31 PM

#14

EDRF also uses cGMP.

The list of Steroid Hormones includes:
Glucocorticoids
Estrogen
Testosterone
Progesterone
Aldosterone
Vit D
Thyroid Hormone

shocked

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