TBR Bio Section IV Passage VII Gestation: hCG stimulating Testosterone?

[manohman]

#45: One of the factors involved in the differentiation of the Wolffian Ducts is Testosterone. The production and secretion of testosterone during this stage of development is under the infulence of:

C: Human Chorionic Gonadotropin


I dont understand how this is the answer and if so, how would one know that? hCG does stimulate the Corpus Luteum to stay in action and keep producing Estrogen and Progesterone. Estrogen is made from Testosterone (Theca cells make testoeterone and pass it to the Follicle cells which convert it to Estrogen).

So super indirectly, i could see how this is why. but theres nothing in the passage to suggest that and the key just says:

"The production of steroid during the early part of gestation is dependent on hCG derived from the placenta".

Is this something i should know/have made the connection for" (testosterone--> estrogne. so if it stimulates estrogen it stimulates testosterone?)

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[Czarcasm]

#45: One of the factors involved in the differentiation of the Wolffian Ducts is Testosterone. The production and secretion of testosterone during this stage of development is under the infulence of:

C: Human Chorionic Gonadotropin


I dont understand how this is the answer and if so, how would one know that? hCG does stimulate the Corpus Luteum to stay in action and keep producing Estrogen and Progesterone. Estrogen is made from Testosterone (Theca cells make testoeterone and pass it to the Follicle cells which convert it to Estrogen).

So super indirectly, i could see how this is why. but theres nothing in the passage to suggest that and the key just says:

"The production of steroid during the early part of gestation is dependent on hCG derived from the placenta".

Is this something i should know/have made the connection for" (testosterone--> estrogne. so if it stimulates estrogen it stimulates testosterone?)

hCG doesn't directly control the production of testosterone, but it does have an essential role in that it maintains the corpus luteum so that embryonic development can even occur. Progesterone and estrogen help maintain and build the uterine lining so that embryonic implanation can occur. Otherwise, the uterine lining would just expel it's contents along with the embryo through menstruation.

Also, as a point of clarification - estrogen and progesterone (released by the corpus luteum) result in feedback inhibition. They inhibit the release of LH and FSH within the anterior pituatary (as well as GnRH in the hypothalamus). So, it's actually LH and FSH that are responsible for stimulating the production of testosterone in theca cells (which later differentiate to estrogen in follicular cells). But notice, this process is inhibited by hCG, which is a good thing because we don't want more follicles to develop during pregnancy!

Regardless, I think the key take away from this question is for you to realize that for any embryonic development to even occur, especially more advanced stages like sexual differentiation, hCG is necessary (again so that the uterine lining is maintained throughout the first trimester).

But if you're curious and want a little more insight into the actual process, here you go: ...before any sexual differentiation can begin, sexual determination must occur first, which in turn depends on the sex chromosomes. This determination will control whether the gonads become testes or ovaries. So, if the embryo is XY - the Y chromosome contains the SRY gene which in turn, encodes a gene product (transcription factor) that will direct the development of the gonads to testis. As the gonads develop into the testis, two cells undergo differentiation. Leydig cells produce testosterone, which promotes development of the Wolffian ducts. These Wolffian ducts in turn differentiate into other structures (vas deferens, seminiferous tubules, etc.) Meanwhile, sertoli cells (the nurshing cells in the testis, produces MIS (Mullerin-Inhibitimg substance) that causes regression of Mullerin ducts. And viola! It's a boy!

 

[manohman]

Ama

hCG doesn't directly control the production of testosterone, but it does have an essential role in that it maintains the corpus luteum so that embryonic development can even occur. Progesterone and estrogen help maintain and build the uterine lining so that embryonic implanation can occur. Otherwise, the uterine lining would just expel it's contents along with the embryo through menstruation.

Also, as a point of clarification - estrogen and progesterone (released by the corpus luteum) result in feedback inhibition. They inhibit the release of LH and FSH within the anterior pituatary (as well as GnRH in the hypothalamus). So, it's actually LH and FSH that are responsible for stimulating the production of testosterone in theca cells (which later differentiate to estrogen in follicular cells). But notice, this process is inhibited by hCG, which is a good thing because we don't want more follicles to develop during pregnancy!

Regardless, I think the key take away from this question is for you to realize that for any embryonic development to even occur, especially more advanced stages like sexual differentiation, hCG is necessary (again so that the uterine lining is maintained throughout the first trimester).

But if you're curious and want a little more insight into the actual process, here you go: ...before any sexual differentiation can begin, sexual determination must occur first, which in turn depends on the sex chromosomes. This determination will control whether the gonads become testes or ovaries. So, if the embryo is XY - the Y chromosome contains the SRY gene which in turn, encodes a gene product (transcription factor) that will direct the development of the gonads to testis. As the gonads develop into the testis, two cells undergo differentiation. Leydig cells produce testosterone, which promotes development of the Wolffian ducts. These Wolffian ducts in turn differentiate into other structures (vas deferens, seminiferous tubules, etc.) Meanwhile, sertoli cells (the nurshing cells in the testis, produces MIS (Mullerin-Inhibitimg substance) that causes regression of Mullerin ducts. And viola! It's a boy!

Amazing thank you. That was awesome. Im also a biology major but your understanding of the physiology and development is superb. Did you learn this through class or texts? Or another resource? I love it haha

 

[justadream]

Ama

Amazing thank you. That was awesome. Im also a biology major but your understanding of the physiology and development is superb. Did you learn this through class or texts? Or another resource? I love it haha

@Czarcasm could probably recite Campbell Biology word for word lol