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1. Steroid hormones (like testosterone and estrogen) regulate gene expression

In the previous tutorials, our discussion of hormones and signalling pathways has focused on activating dormant enzymes in the cytoplasm. This allows for quick responses, such as quickly breaking down glycogen into glucose for the fight or flight response. That’s why hormones are key components of homeostasis: the dynamic maintenance of optimal internal conditions, despite changes in the external environment.

Steroid hormones can have longer term effects on cells and organisms, and these effects involve the regulation of genes, switching them on and off, which changes the proteins a cell produces. Just think, for a moment, about the effect steroid hormones like testosterone and estrogen had on your body when you went through puberty. These hormones brought about long term changes in your body’s form (everything from the Adam’s apple in males to breasts in females) and function (sexual maturation in both sexes, the start of ovulation and menstruation in females).

How do steroid hormones work to activate genes? Let’s take a look at two of the most famous steroid hormones.

[qwiz qrecord_id=”sciencemusicvideosMeister1961-testosterone and estrogen (M11)”]

[h]Testosterone and estrogen

[i]

Estrogen

Testosterone

[q]How would you classify these hormones?

Estrogen

Testosterone

[c]Y2FyYm9oeWRyYXRl[Qq]

[f]Tm86IGNhcmJvaHlkcmF0ZXMgYXJlIHBvbHltZXJzIG9mIG1vbm9zYWNjaGFyaWRlcyAoc2ltcGxlIHN1Z2FycykuIE5vIHN1Z2FycyBhcmUgc2hvd24gYWJvdmUu[Qq]

[c]bGlw aWQ=[Qq]

[f]RXhjZWxsZW50OiBlc3Ryb2dlbiBhbmQgdGVzdG9zdGVyb25lIGFyZSBsaXBpZHMu[Qq]

[c]cHJvdGVpbg==[Qq]

[f]Tm86IHByb3RlaW5zIGFyZSBwb2x5bWVycyBvZiBhbWlubyBhY2lkcywgYW5kIGhhdmUgdmVyeSBjb21wbGV4IHRocmVlIGRpbWVuc2lvbmFsIHNoYXBlcy7CoE1ha2UgYW5vdGhlciBjaG9pY2UgbmV4dCB0aW1lLg==[Qq]

[c]bnVjbGVpYyBhY2lk[Qq]

[f]Tm86IG51Y2xlaWMgYWNpZHMgYXJlIHBvbHltZXJzIG9mIG51Y2xlb3RpZGVzLiBNYWtlIGFub3RoZXIgY2hvaWNlIG5leHQgdGltZS4=[Qq]

[q]In terms of their interaction with water, molecules like estrogen and testosterone are

Estrogen

Testosterone

[c]SHlkcm9w aG9iaWM=[Qq]

[f]WWVzLiBEZXNwaXRlIHRoZSBoeWRyb3h5bCBncm91cHMsIHRoZSBiaWcgZnVzZWQgY2FyYm9uIHJpbmdzIHNob3duIGFib3ZlIGFyZSBnb2luZyB0byBtYWtlIHRoaXMgbW9sZWN1bGUgbm9uLXBvbGFyLCBhbmQgdGhlcmVmb3JlIGh5ZHJvcGhvYmljLg==[Qq]

[c]SHlkcm9waGlsaWMu[Qq]

[f]Tm8uIE5vdGljZSB0aGUgZm91ciBmdXNlZCBjYXJib24gcmluZ3MgdGhhdCBtYWtlIHVwIHRoZSBidWxrIG9mIHRoZXNlIG1vbGVjdWxlcy4gSG93IGRvIHlvdSB0aGluayB0aGVzZSByaW5ncyBhcmUgZ29pbmcgdG8gaW50ZXJhY3Qgd2l0aCB3YXRlcj8=[Qq]

[x]So, note these two key ideas. Steroid hormones are lipids, and they’re hydrophobic. That sets up the way they’ll interact with cell membranes, which you’ll learn about below.

[/qwiz]

 

A general scheme for steroid hormone action is shown at right. The first thing to note is that because steroid hormones (“F”) are lipids (and therefore non-polar and hydrophobic), they, can pass right through the cell’s phospholipid bilayer (“B”) and diffuse into the cytoplasm (“C”).

Floating in the cytoplasm of the cells that are the targets for a steroid hormone are mobile receptors (“G”). The hormone binds with the receptor forming a receptor-hormone complex (“H”). This complex can pass through the nuclear membrane (“D”) at a nuclear pore (“E”), where it binds with DNA (“J”) and acts as a transcription factor (“I”).

Transcription factors cause genes to be expressed. That involves production of messenger RNA (“K”). The RNA diffuses out of the nucleus and into the cytoplasm. There, the messenger RNA is read by a ribosome (“L”), and then transcribed into protein (“M”). And to connect this back to puberty, this protein is what the changes in your body’s form and function were all about. Protein is the tissue that makes up the increased muscle mass that you gained if you’re a male. Protein is what makes up the skin and underlying structure of breast tissue if you’re female.

2. Some Water-Soluble Hormones have Signal Transduction Pathways that Regulate Genes

While steroid hormones are typically associated with gene regulation, there are some water soluble (polar) hormones that also work though regulating genes.

One example of this is growth hormone, which is secreted by the pituitary gland, in the brain. As its name indicates, growth hormone stimulates cell reproduction, and plays a key role in animal development. Click here to read more about growth hormone on Wikipedia.

Composed of 191 amino acids, growth hormone is much too big and polar to pass through the phospholipid bilayer. Consequently, it works through a mechanism that’s similar to what’s shown at left (though the actual pathway for growth hormone is much more complicated).

The process starts with the hormone being released from a vesicle in the cell of a hormone-producing gland (“1”). The hormone diffuses from the extracellular space into the bloodstream (“2”) and then circulates throughout the body, diffusing out of the bloodstream (“3”) and binding with target cells that have a complementary receptor (“4”). After binding with the receptor, the message needs to be transduced through a signal transduction pathway (“5”) in the cytoplasm (“B”). The last molecule in this pathway (“6”) diffuses into the nucleus (“C”) through a nuclear pore, and then interacts with the cell’s DNA (“7”), either activating or deactivating genes.

3. Quiz: Hormones and Gene Regulation

[qwiz random=”true” qrecord_id=”sciencemusicvideosMeister1961-Hormones and Gene Regulation (M11)”]

[h] Hormones and Gene Regulation

[i]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6229b971a1fff” question_number=”1″] In the diagram below, which letter represents the cell membrane?

[textentry single_char=”true”]

[c]IE I=[Qq]

[f]IFllcy4g4oCcQuKAnSByZXByZXNlbnRzIHRoZSBtZW1icmFuZS4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgc2lnbmFsIGNvbWVzIGZyb20gb3V0c2lkZSB0aGUgY2VsbCwgYW5kLCBpbiB0aGUgY2FzZSBvZiBhIHN0ZXJvaWQgaG9ybW9uZSwgZGlmZnVzZXMgdGhyb3VnaCB0aGUgbWVtYnJhbmUuIElmICYjODIyMDtBJiM4MjIxOyByZXByZXNlbnRzIHRoZSBjZWxsIGV4dGVyaW9yLCB3aGljaCBsZXR0ZXIgcmVwcmVzZW50cyB0aGUgbWVtYnJhbmU/
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6223c21329bff” question_number=”2″] In the diagram below, which letter could represent a steroid hormone (such as testosterone or estrogen)?

[textentry single_char=”true”]

[c]IE Y=[Qq]

[f]IFllcy4g4oCcRuKAnSByZXByZXNlbnRzIGEgc3Rlcm9pZCBob3Jtb25lLg==[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgc2lnbmFsIGNvbWVzIGZyb20gb3V0c2lkZSB0aGUgY2VsbCwgdGhlbiBkaWZmdXNlcyB0aHJvdWdoIHRoZSBtZW1icmFuZS4gSWYgJiM4MjIwO0EmIzgyMjE7IHJlcHJlc2VudHMgdGhlIGNlbGwgZXh0ZXJpb3IsIHdoaWNoIGxldHRlciBjb3VsZCByZXByZXNlbnQgdGhlIHNpZ25hbCB0aGF0JiM4MjE3O3MgYWJvdXQgdG8gZW50ZXIgaW50byB0aGUgY2VsbD8=
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|621e5fb7aa7ff” question_number=”3″] In the diagram below, which letter could represent a cytoplasmic receptor (before it binds with the signal)?

[textentry single_char=”true”]

[c]IE c=[Qq]

[f]IFllcy4g4oCcR+KAnSByZXByZXNlbnRzIGEgY3l0b3BsYXNtaWMgcmVjZXB0b3Iu[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgc2lnbmFsIGNvbWVzIGZyb20gb3V0c2lkZSB0aGUgY2VsbCwgdGhlbiBkaWZmdXNlcyB0aHJvdWdoIHRoZSBtZW1icmFuZSwgdGhlbiBiaW5kcyB3aXRoIGEgY3l0b3BsYXNtaWMgcmVjZXB0b3IuIElmICYjODIyMDtGJiM4MjIxOyByZXByZXNlbnRzIHRoZSBzaWduYWwsIHRoZW4gd2hhdCBpbnNpZGUgdGhlIGNlbGwgY291bGQgcmVwcmVzZW50IGFuIGVtcHR5IHJlY2VwdG9yIHRoYXQgdGhlIHNpZ25hbCBjYW4gYmluZCB3aXRoPw==
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6217d356393ff” question_number=”4″] In the diagram below, which letter shows a receptor/hormone complex interacting with DNA?

[textentry single_char=”true”]

[c]IE k=[Qq]

[f]IFllcy4g4oCcSeKAnSBzaG93cyBhIHJlY2VwdG9yL2hvcm1vbmUgY29tcGxleCBpbnRlcmFjdGluZyB3aXRoIEROQS4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgc2lnbmFsIGNvbWVzIGZyb20gb3V0c2lkZSB0aGUgY2VsbCwgdGhlbiBkaWZmdXNlcyB0aHJvdWdoIHRoZSBtZW1icmFuZSwgdGhlbiBiaW5kcyB3aXRoIGEgY3l0b3BsYXNtaWMgcmVjZXB0b3IsIHdoaWNoIHRoZW4gZGlmZnVzZXMgaW50byB0aGUgbnVjbGV1cyB3aGVyZSBpdCBpbnRlcmFjdHMgd2l0aCBETkEuIEZpbmQgRE5BIGluc2lkZSB0aGUgbnVjbGV1cywgZmlndXJlIG91dCB3aGF0IHRoZSByZWNlcHRvciBpcywgYW5kIHlvdSYjODIxNztsbCBoYXZlIHlvdXIgYW5zd2VyLg==
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6211b6b702bff” question_number=”5″] In the diagram below, which letter shows RNA that’s just been transcribed as a result of the hormone/receptor complex having interacted with the cell’s DNA?

[textentry single_char=”true”]

[c]IE s=[Qq]

[f]IFllcy4g4oCcS+KAnSBzaG93cyBSTkEgdGhhdCYjODIxNztzIGp1c3QgYmVlbiB0cmFuc2NyaWJlZCBhcyBhIHJlc3VsdCBvZiB0aGUgaG9ybW9uZS9yZWNlcHRvciBjb21wbGV4IGhhdmluZyBpbnRlcmFjdGVkIHdpdGggdGhlIGNlbGwmIzgyMTc7cyBETkEu[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiAmIzgyMjA7SCYjODIyMTsgc2hvd3MgYSByZWNlcHRvci9ob3Jtb25lIGNvbXBsZXggaW4gdGhlIGN5dG9wbGFzbS4gTm93LCBmaW5kIEROQSBpbiB0aGUgbnVjbGV1cy4gTm93LCBmaW5kIGEgc2luZ2xlIHN0cmFuZGVkIG1vbGVjdWxlIHRoYXQmIzgyMTc7cyBiZWVuIHByb2R1Y2VkIGFzIGEgcmVzdWx0IG9mIHRoZSBpbnRlcmFjdGlvbiBiZXR3ZWVuIHRoZSByZWNlcHRvci9ob3Jtb25lIGNvbXBsZXggYW5kIEROQSwgYW5kIHlvdSYjODIxNztsbCBoYXZlIHlvdXIgYW5zd2VyLg==
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|620c545b837ff” question_number=”6″] In the diagram below, which letter shows a nuclear pore?

[textentry single_char=”true”]

[c]IE U=[Qq]

[f]IFllcy4g4oCcReKAnSBzaG93cyBhIG51Y2xlYXIgcG9yZS4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBOdWNsZWFyIHBvcmVzIGFyZSBwYXNzYWdld2F5cyBmb3IgbWF0ZXJpYWxzIHRvIGVudGVyIGFuZCBsZWF2ZSB0aGUgbnVjbGV1cy4gRmluZCB0aGUgbnVjbGVhciBtZW1icmFuZSwgYW5kIHRoZW4gbG9jYXRlIGEgbnVjbGVhciBwb3JlLg==
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6206a77e87bff” question_number=”7″] In the diagram below, which letter shows a ribosome?

[textentry single_char=”true”]

[c]IE w=[Qq]

[f]IFllcy4g4oCcTOKAnSBzaG93cyBhIHJpYm9zb21lLg==[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBSaWJvc29tZXMgdHJhbnNsYXRlIHRoZSBtZXNzYWdlcyBpbiBSTkEgaW50byBwcm90ZWluLCBhbiBhY3Rpdml0eSB0aGF0IG9jY3VycyBpbiB0aGUgY3l0b3BsYXNtLiBJZiAmIzgyMjA7SyYjODIyMTsgaXMgUk5BIGlzIHRoZSBudWNsZXVzLCB0aGVuIHdoYXQgbGV0dGVyIGNvdWxkIGluZGljYXRlIGEgcmlib3NvbWUgdHJhbnNsYXRpbmcgdGhhdCBSTkEgaW50byBwcm90ZWluPw==
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|6200faa18bfff” question_number=”8″] In the diagram below, which letter shows a protein that’s produced as the cellular response to the steroid hormone signal?

[textentry single_char=”true”]

[c]IE 0=[Qq]

[f]IFllcy4g4oCcTeKAnSBzaG93cyBhIHByb3RlaW4gdGhhdCYjODIxNztzIGJlaW5nIHN5bnRoZXNpemVkIGFzIGEgcmVzdWx0IG9mIHRoZSBob3Jtb25lIHNpZ25hbCB0aGF0IGRpZmZ1c2VkIGludG8gdGhlIGNlbGwsIHRoZW4gYm91bmQgd2l0aCBhIHJlY2VwdG9yIGFuZCBhY3RpdmF0ZWQgYSBnZW5lLCB1bHRpbWF0ZWx5IHJlc3VsdGluZyBpbiB0aGlzIHByb3RlaW4mIzgyMTc7cyB0cmFuc2xhdGlvbi4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBGb3Igc3Rlcm9pZCBob3Jtb25lcywgdGhlIGNlbGx1bGFyIHJlc3BvbnNlIGlzIHRoZSBwcm9kdWN0aW9uIG9mIGEgcHJvdGVpbi4gSWYgJiM4MjIwO0wmIzgyMjE7IHJlcHJlc2VudHMgYSByaWJvc29tZSwgdGhlIGNlbGwmIzgyMTc7cyBwcm90ZWluIGZhY3RvcnksIHRoZW4gd2hhdCBjb3VsZCByZXByZXNlbnQgYSBwcm90ZWluIHRoYXQgdGhpcyByaWJvc29tZSBpcyBzeW50aGVzaXppbmc/
Cg==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61fb98460cbff” question_number=”9″] In the diagram below, “I” represents [hangman].

[c]IHJlY2VwdGlvbg==[Qq]

[f]IFllcywgJiM4MjIwO0kmIzgyMjE7IHJlcHJlc2VudHMgcmVjZXB0aW9uLg==
Cg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61f5c62852bff” question_number=”10″] In the diagram below, “II” represents [hangman].

[c]IHRyYW5zZHVjdGlvbg==[Qq]

[f]IFllcywgJiM4MjIwO0kmIzgyMjE7IHJlcHJlc2VudHMgdHJhbnNkdWN0aW9uLg==
Cg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61f0194b56fff” question_number=”11″] In the diagram below, “III” (and “4”) represents a cellular [hangman].

[c]IHJlc3BvbnNl

Cg==[Qq]

[f]IFllcywgJiM4MjIwO0lJSSYjODIyMTsgcmVwcmVzZW50cyB0aGUgY2VsbHVsYXIgcmVzcG9uc2Uu[Qq]


[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61ea6c6e5b3ff” question_number=”12″] The diagram below shows a hormone that would be chemically classified as a [hangman].

[c]IHN0ZXJvaWQ=[Qq]

[f]IFllcywgVGhlIGRpYWdyYW0gaXMgc2hvd2luZyBob3cgYSBzdGVyb2lkIGhvcm1vbmUgYWZmZWN0cyBpdHMgdGFyZ2V0IGNlbGwu[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61e4e4d21dbff” question_number=”13″] In the diagram below, which number or letter shows a hormone in a vesicle in a hormone secreting cell?

[textentry single_char=”true”]
[c]ID E=

Cg==[Qq]

[f]IFllcy4g4oCcMeKAnSBzaG93cyBhIGhvcm1vbmUgaW4gYSB2ZXNpY2xlIGluIGEgaG9ybW9uZSBzZWNyZXRpbmcgY2VsbC4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBWZXNpY2xlcyBhcmUgbWVtYnJhbmUtZW5jbG9zZWQgYnViYmxlcyB0aGF0IG9mdGVuIGNvbnRhaW4gYSBzdWJzdGFuY2UgdGhhdCBhIGNlbGwgaXMgYWJvdXQgdG8gZXhwb3J0LiBXaGljaCBudW1iZXIgaXMgbmVhciBzb21ldGhpbmcgdGhhdCBjb3VsZCBmaXQgdGhhdCBkZXNjcmlwdGlvbj8=[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

 

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61df12b463bff” question_number=”14″] In the diagram below, which number or letter shows a signal transduction pathway?

[textentry single_char=”true”]
[c]ID U=

Cg==[Qq]

[f]IFllcy4g4oCcNeKAnSBzaG93cyBhIHNpZ25hbCB0cmFuc2R1Y3Rpb24gcGF0aHdheS4=[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgc2lnbmFsIHRyYW5zZHVjdGlvbiBwYXRod2F5IG9jY3VycyBpbiB0aGUgY3l0b3BsYXNtLCB3aGljaCBpcyByZWdpb24gJiM4MjIwO2IuJiM4MjIxOyBJbiB0aGlzIGNhc2UsIHRoZSBwYXRod2F5IGlzIHRha2luZyBhIG1lc3NhZ2UgZnJvbSB0aGUgbWVtYnJhbmUgaW50byB0aGUgbnVjbGV1cy4=[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61d65787ccbff” question_number=”15″] What number or letter below shows a molecule from a signaling pathway interacting with DNA?

[textentry single_char=”true”]
[c]ID Y=

Cg==[Qq]

[f]IFllcy4g4oCcNuKAnSBzaG93cyBhIHByb3RlaW4ga2luYXNlIGludGVyYWN0aW5nIHdpdGggRE5BLg==[Qq]

[c]ICo=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBETkEgaXMgaW5zaWRlIHRoZSBudWNsZXVzLCB3aGljaCBpcyByZWdpb24gJiM4MjIwO2MuJiM4MjIxOw==[Qq]

[c]IEVudGVyIGxldHRlcg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61d0f52c4d7ff” question_number=”16″] Because of the way the hormone is binding with a membrane receptor, we can conclude that it must be [hangman].

[c]IHBvbGFy[Qq]

 

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61ca8e0b9a7ff” question_number=”17″] Number “5” below is a signal [hangman] pathway.

[c]IHRyYW5zZHVjdGlvbg==[Qq]

[q json=”true” dataset_id=”SMV_Hormones and Gene Regulation (cell communication)|61c1d2df037ff” question_number=”18″] The diagram below shows how a hormone circulates everywhere in the body, but only has an effect in [hangman] cells.

[c]IHRhcmdldA==[Qq]

[x]

[restart]

[/qwiz]

 Next Steps

This tutorial ends this series of tutorial about cell signaling.