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Old 01-24-2012
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Zygote Reproductive system Embryology; Development of Gender

hey have a few doubts regarding these cases , would be glad if anyone could help ...

1) In 17a-hydroxylase deficiency why do they dont form internal organs ??? according to the SRY gene flow chart the testes would produce MIF and inhibit female gonad development but this has no involvement of testosterone ???

2) similarly didnt understand why in Absence of sertoli cell as mentioned in FA both male and female internal organs are formed ??? if there is NO MIF then only female organs should form ??????
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Old 01-24-2012
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1. I have FA 2010 and it doesn't say anything about not developing sex organs.

Males are pseudohermaphrodites (externally they are phenotypic females but no internal reproductive structures). What I get from this is that since MIF is present the paramesonephric (mullerian tissue) undergoes apoptosis. That's all MIF does. For the mesonephric (wolffian duct) structures to develop fetal testosterone is required. In this case since 17 a-hydroxylase is deficient testosterone cannot be produced for these structures to develop. Hence outside female but no internal structures.

Females are externally phenotypic female with normal internal sex organs but lacking secondary sexual characteristics (sexual infantilism). What I get from this is that since MIF is not present the paramesonephric (mullerian tissue) develop normally. So the external and internal female structures are present but the female doesn't go through puberty and develop as a normal female. Since 17 a-hydroxylase is deficient there is no production of androgens and hence estradiol or estrone. Therefore the female doesn't experience further development of the genitalia, pubic hair, breasts, female fat distribution and has amenorrhea.



2. I have looked through all the relevant sections of FA 2010 and I cannot find any mention of non-development of both male and female structures in the absence of sertoli cells. I couldn't even find a mention of absence of sertoli cells.

All it says is that the default development is the paramesonephric duct. So in the absence of sertoli cells, you are correct in saying there is no MIF and female structures will develop.

Are you sure you read that in FA???

Last edited by haga; 01-24-2012 at 11:14 PM.
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thank you , yes its in FA on pg no 486 but its the 2011 edition , thank you i really missed the part that both external and internal organ development depends on testosterone and DHT ... In FA is written that in absence of sertoli cells or MIF both male and female organs are formed ... now i understand that its due to testosterone developing male organs and lack of MIF leads to development of female organs ...... Even in the older edition you may find it as a side note along the SRY gene flow chart ......

Thank you , it was just in front of me but still could not get it ....
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Old 01-25-2012
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males:
so 17a-hydroxylase deficiency means no androgen production (test or dht), right?

and so neither male internal (test-induced) or external genitalia (dht-induced) will be formed, right?

yet, MIF is still being produced by the sertoli cells and therefore there will not be female internal genitalia either (MIF inhibits paramesonephric duct from forming internal female genitalia).

and so without male external genitalia being produced, the default is female external genitalia are produced?

females:

no androgens promotes female genitalia to be produced... so umm whats the defect in females that have 17a-hydroxylase deficiency?
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Old 01-25-2012
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Quote:
Originally Posted by khushi.chahal View Post
males:
so 17a-hydroxylase deficiency means no androgen production (test or dht), right?

and so neither male internal (test-induced) or external genitalia (dht-induced) will be formed, right?

yet, MIF is still being produced by the sertoli cells and therefore there will not be female internal genitalia either (MIF inhibits paramesonephric duct from forming internal female genitalia).

and so without male external genitalia being produced, the default is female external genitalia are produced?

females:

no androgens promotes female genitalia to be produced... so umm whats the defect in females that have 17a-hydroxylase deficiency?
Yes , in Males the external genitalia are female and in female there is no defect in sex organs both internal and external are normal the defect is in maturation of these organs which is called sexual infantilism in which there is lack of development of secondary sexual features .....
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I hope this will help





SRY gene on Y
xxxxxx|
xxxxxx|
llllllllllll\/
Testes-Differentiating Factor (TDF)
xxxxxx|
llllllllllll\/
development of testes from indifferent gonad
xx|xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx|
lll\/llllllllllllllllllllllllllllllllllllllllllllllllll llllllllllllllllllllllll\/
SertolixxxxxxxxxxxxxxxxxxWolfian d.xxxxLeydig
x|xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\xxxxxxxx|
l\/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \x Testosterone
MIFxxxxxxxxxxxxxxxxxxxxxxxxxxxxx /xxxxxxx|
x|xxxxxxxxxxxxxxxxxxxxxxxMale Internalxxxxl|
l\/xxxxxxxxxxxxxxxxxxxxx(vas&epididymis)lxx\/
Involution ofxxxxxxxxxxxxxxxxxxxxxxxxxxxxDHT
paramesonephric ductxxxxxxxxxxxxxxxxxxxxxl|
xxxxxxxxxxxxxxxxxxxxxxxxxxxGenit.Tubercle----->Male External
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